Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005
Contents
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel
Nortel Confidential
What’s new
Terms that apply to the following features were added to this document:
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•
Attention: To ensure that you are using the most current version of an NTP,
check the current NTP list in NN10600-000 Nortel Multiservice Switch 7400/
15000/20000 What’s New.
Secure shell (Ssh) on Nortel Multiservice Switch 15000 and 20000
The following terms were updated for this feature:
•
•
•
The following terms were added for this feature:
•
•
Load Re-balancing on Parallel Links
The following term was added for this feature:
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Terminology
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List of terms
802.3
An IEEE standard defining Ethernet communications.
AAL
AAL1
AAL2
AAList
AAL2 channel identifier (CID)
A numerical value associated with a virtual channel connection (VCC)
narrowband timeslot. For non-switched trunks, the association is fixed when
the VCC is established. For switched trunks, the association is made for each
cell.
AAL-5
A-bit signaling
ABR
ABS
1
2
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abstract syntax notation 1 (ASN.1)
A complex data description language used for defining data in a machine-
independent manner. ASN.1 is defined in ITU-T and ISO specifications.
ACC
acceptable routing path
A path that satisfies the traffic requirements for an ATM PNNI call and for
which the optimization metric is within the specified variance interval.
Acceptable routing paths are used for ATM network load balancing.
access call control (ACC)
Nortel Multiservice Switch protocol-independent software that controls the
progress and state of a call.
access delay
The time it takes to clock a frame or cell into or out of an access port on a
Nortel Multiservice Switch node. In a Multiservice Switch network, the
calculated value for access delay includes the serialization delay only. Access
devices are assumed to be located close enough to a Multiservice Switch
node so that propagation delay is ignored.
access module (AM)
A DPN-100 device that provides user access, termination, and concentration,
and local data switching. Access modules can use Nortel Multiservice Switch
nodes as a backbone device.
access protocol control (APC)
Software residing on a Nortel Multiservice Switch node. APC software support
OSI Layers 1, 2, and 3 CCS message handling and call processing functions
for connections with PBXs. See also common channel signaling (CCS)
accounting gateway
A software application that runs on a workstation and is used to convert
accounting records into a format usable by an IBM or VAX billing host.
accounting meter
Collects data for the frame relay egress accounting and ATM accounting
features based on the end-user traffic at the entry and exit points of the
networks. The meter generates accounting records from the collected data.
acknowledgment
A message that the receiving end sends to the source to indicate that it has
received a transmission in good order.
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List of terms
ACR
active alarm list
A list of active alarms, residing on each running card, that have been raised
but not yet cleared.
actual shaping rate (ASR)
The shaping rate that is applied to a given ATM virtual channel connection
(VCC) or virtual path connection (VPC). This value is based on the traffic
descriptor type parameters and the quality of service specified for the
connection, and is determined through traffic shaping.
adaptive differential pulse code modulation (ADPCM)
A widely used voice compression technique standardized by the ITU-T.
address plan
Specifies the format of the addresses that identify the network elements to
which Nortel Multiservice Switch nodes can route packets. The address plan
is known by every node capable of receiving such packets. The plan can be
either internal or external to Multiservice Switch. Multiservice Switch uses the
external DPN-100 address plan that combines ITU-T specifications X.121 and
E.164 with DPN-100 RID/MID addressing.
address prefix
A string of bits that forms the lead portion of one or more ATM addresses. The
length of the prefix is a maximum of 152 bits.
address resolution protocol (ARP)
A mechanism for mapping an IP network layer address to a data link layer
address.
address scope
In ATM PNNI networking, a configured value for each node that participates in
the network. Address scope is assigned to the node address and defines the
highest level up to which the node advertises this address in the PNNI
hierarchy.
address space manager (ASM)
A component in a LEN node that assigns and frees session addresses.
address summarization
In ATM PNNI networking, reduces the amount of addressing information that
needs to be distributed throughout the network. Address summarization
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adjacency
A relationship formed between selected neighboring routers for the purpose
of exchanging routing information. Not every pair of neighboring routers
becomes adjacent.
adjacent network identifier (ANID)
A numeric identifier assigned to an adjacent network that is directly connected
to this network through at least one X.25 or X.75 gateway.
ADPCM
ADTF
advertisement scope
Advisor
A Multiservice Data Manager toolset.
agent
Network management software components that are contained in managed
entities such as routers, concentrators, and host computers. These
components monitor the operation of the managed entity by maintaining a
collection of objects in the management information base (MIB).
Agents communicate with corresponding managers.
aggregate policy
An internetworking policy through which the border gateway protocol (BGP)
combines the characteristics of different routes and advertises this
combination as a single route. Aggregation reduces the data that a BGP
speaker stores and exchanges with another BGP speaker.
AINI
AIR
AIS
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alarm agent
An entity residing on every function processor (FP) and control processor
(CP) that receives alarm events from a variety of services/applications.
alarm
Notification of an unusual, important, or abnormal event. An event can be
degradation of service or quality of service conditions, processing errors, out-
of-service conditions, software errors, administrative conditions, or security
violations.
alarm collector
An entity residing on the active control processor (CP) that receives alarms
from its alarm agents.
alarm indication signal (AIS)
1
2
A signal transmitted in lieu of the normal signal to maintain transmission
continuity and to indicate to the receiving equipment that there is a
transmission interruption located either at the equipment originating the
AIS signal or upstream of that equipment.
A signal transmitted in the downstream direction from a point of failure.
The AIS signal is used at the physical and ATM layers.
A-law
A technique for translating pulse code modulated voice into 64 kbit/s digital
voice channels. A-law is used in countries that use E1 function processors.
allowed cell rate
In ATM ABR networking, the rate at which the ABR source is allowed to
transmit cells into the network. The allowed cell rate for an ABR connection
varies dynamically as resource availability changes along the connection.
allowed cell rate decrease time factor (ADTF)
In ATM ABR networking, the time interval permitted between sending forward
resource management (FRM) cells before the allowed cell rate is decreased
to the initial cell rate (ICR). If the source does not transmit an
FRM cell for a period of ADTF centiseconds (hundredths of a second), it
reduces its allowed cell rate to the value of its ICR. If the allowed cell rate is
already at or below ICR, further rate reductions are defined by the ABR FRM
cell limit.
allowed information rate (AIR)
A pro-active congestion control mechanism used by the network that reduces
allocated bandwidth when congestion occurs and by doing so discards frames
in a controlled fashion.
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List of terms
alternate clock master
For Nortel Multiservice Switch 7400 nodes, the bus tap in slot 0 or slot 15,
which is the alternate clock signal for a backplane bus. This term can also be
alternate mark inversion (AMI)
A digital line encoding technique in which a zero is transmitted by no pulse
while a one is transmitted by a pulse opposite in polarity to the previous pulse.
alternate path
An optional pre-determined path for a specified path connection. The
alternate path acts as a backup in case the primary path fails.
AM
AM cluster
A set of DPN-100 access modules (AM) and routing identifiers (RID), where
these AMs and RIDs have been grouped for routing purposes. Each AM
cluster can have up to two RIDs. Each RID can be a member of more than one
AM cluster.
American standard code for information interchange (ASCII)
A standards-based format for text files, in which each character is represented
as a 7-digit binary string. There are 128 characters. There are variations,
notably for Windows NT and derivative operating systems and IBM System
390 servers. There is also extended ASCII, which includes up to 256
characters.
AMI
American National Standards Institute (ANSI)
An organization that establishes voluntary industry standards.
ancestor node
An ancestor node is a node that has a parent relationship to a given node.
ANID
ANSI
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APC
APS
application
Nortel Multiservice Switch software is partitioned into distinct software
applications. Applications contain features that are loaded on cards to provide
services. A Multiservice Switch node can run multiple software applications
simultaneously. An example of an application is frame relay service. See also
application journaling
Represents the journaling of operational data between active and standby
applications.
application-specific integrated circuit (ASIC)
An integrated circuit that performs a set of specific processes more quickly
and efficiently than a generic processor.
application version (AV)
A particular version (or release) of an application.
application version list (AVL)
Specifies the version level of all applications that are configured to run on a
Nortel Multiservice Switch node.
AQM
Architect for Passport
A Multiservice Data Manager toolset.
area border router (ABR)
Connects one or more OSPF areas and the backbone in IP networking. ABRs
condense or summarize the topological data of their attached areas for
distribution on the backbone. The backbone in turn distributes the information
to other areas.
ARP
AS
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ASBR
ASCII
ASIC
ASM
ASN.1
ASPEN
ASR
AS weight policy
associated signaling
Uses one dedicated path between nodes as the signaling link.
asynchronous transfer mode (ATM)
A technology that provides access to a network by multiplexing user
information into fixed-length units called cells. ATM forms the basis for
broadband networks.
ATM
ATM accounting
Collects usage information in the form of cell counts for ATM connections. The
service provider can use this information to bill customers or for test purposes,
statistics, network engineering, and planning.
ATM adaptation layer (AAL)
The standards layer that allows multiple applications to convert data to and
from a set of ATM cells. AAL translates higher layer services into the size and
format of an ATM cell.
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ATM adaptation layer type 1 (AAL1)
An AAL protocol used to transfer constant bit rate traffic such as voice and
video.
ATM adaptation layer type 2 (AAL2)
An AAL protocol used to transfer variable bit rate traffic.
ATM adaptation layer type 5 (AAL-5)
An AAL protocol used to transfer variable bit rate, delay-tolerant, connection-
oriented traffic that requires minimal sequencing or error detection support.
ATM anycast capability
An ATM routing and signaling feature that allows a user to request a point-to-
point connection to a single ATM end system that is part of an ATM group.
ATM bearer service (ABS)
Nortel Multiservice Switch ATM node’s bearer service allows ATM users and
external equipment (ATM hubs, routers, workstations, servers, and video-
conferencing equipment) access to the Multiservice Switch network. This
service provides sequence-preserving connection-oriented cell transfer
between source and destination with a defined quality of service and
throughput.
ATM bus controller (ABC)
A bus controller on a Nortel Multiservice Switch ATM node’s function
processor.
ATM interface CAC (AtmIf-CAC)
A connection admission control (CAC) technique that applies to independent
virtual channel connections (VCC) and virtual path connections (VPC) under
AtmIf-CAC
ATM inter-network interface (AINI)
ATM Forum standard signaling protocol that provides interconnection
between Nortel Multiservice Switch nodes as well as interconnection between
Multiservice Switch and non-Multiservice Switch nodes (Nortel Networks-
family devices and devices from other vendors).
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ATM IP function processor
Nortel Multiservice Switch ATM node function processor that uses the
Multiservice Switch queue controller (PQC) and ATM queue manager (AQM)
ASICs to provide enhanced cell processing and ATM traffic management
capabilities.
ATM layer
A layer in the B-ISDN protocol stack that transfers ATM cells. It is positioned
between the physical layer and the AAL.
ATM link
A standards-based ATM connection.
ATM logical multicasting
Logical multicasting creates additional VCCs on the same output port of a
node, thus allowing more than one replicated copy of the same cell to be
delivered to the same output port. This in turn enables cell replication for
transport over ATM networks that do not support multicasting.
ATM multiprotocol encapsulation service
A service that supports two encapsulation methods for carrying
connectionless network interconnect traffic over AAL-5. The first method is
logical link control (LLC) encapsulation, which permits multiple protocols over
a single ATM virtual circuit (VC). The second method is VC encapsulation,
which permits one protocol over each ATM VC.
ATM network multicasting
Network multicasting is performed at each node in the ATM network to
determine where branch points for a PMP call are required. Once a branch
point is identified, spatial multicasting techniques are utilized to replicate the
cell stream.
ATM networking
Encompasses the standards-based UNI, IISP, AINI, and PNNI routing and
signaling protocols.
ATM queue manager (AQM)
A hardware chip on ATM IP function processors. The AQM performs traffic
management functions such as per-VC queuing, shaped fair queuing, and
processing for available bit rate (ABR) traffic.
ATM spatial multicasting
Spatial multicasting delivers replicated cells to different output ports on the
same node, thus permitting the routing of cells from the same node to different
destinations.
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List of terms
attribute
Defines the behavior or information associated with a specific component.
Attributes are either operational or provisionable. See also operational
attribute type
Specifies the structure of the attribute’s value (for example, decimal, hex,
BCD, integer, or IP address).
attribute value
The current setting for an attribute. The structure of the value is dictated by the
type of attribute.
automatic protection switching (APS)
APS detects faults in SONET or SDH lines that are connected to the active
function processor. Under line APS, two SONET or SDH lines are defined:
working and protection. Either line can be active. Line APS monitors the line
that is active and when necessary causes the card to switch to the other line.
autonomous system (AS)
An autonomous system is one or more networks that are under the control of
one enterprise. These networks are usually under the control of a single
routing protocol.
autonomous system boundary router (ASBR)
An ASBR is a gateway between autonomous systems. ASBRs are the
backbone of the Internet.
autonomous system weight policy
The autonomous system weight policy allows you to set a preference for some
autonomous systems and discriminate against others. You can assign each
autonomous system a weight, where the border gateway protocol (BGP)
prefers the path with lowest weight.
AV
AVL
availability
The percentage of time during which a device or service is ready for use.
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availability-bit signaling
The availability-bit (A-bit) signaling technique exchanges availability status
between the two ends of a frame relay permanent virtual channel (PVC)
connection. A-bit signaling permits each end of a PVC to determine if the
remote end is ready to process data.
availability message packet (AMP)
An availability message packet (AMP) is a status message sent by a hunt
group member to its hunt group server. A hunt group member sends an AMP
each time its availability status changes significantly.
available bit rate (ABR)
An ATM service category. ABR permits dynamic allocation of bandwidth to
applications that are highly tolerant of cell delay and delay variance, such as
LAN interconnection. ABR traffic is characterized as very bursty.
available cell rate (ACR)
The available capacity of an ATM link. In general, ACR refers to links that are
already in use by one or more ATM connections.
B-channel
B-ICI
B3ZS
B8ZS
backbone
A group of interconnected core nodes that normally tandem traffic. A
backbone node exchanges full topology information with all nodes in the same
topology region that are not cluster nodes. The backbone exchanges limited
routing and no topology information with clusters. The backbone does not
exchange any information with nodes in other topology regions.
backbone border node
Nortel Multiservice Switch nodes that reside on a backbone boundary,
connected by backbone-cluster border links to cluster nodes.
backbone node
Nortel Multiservice Switch nodes that reside within a backbone.
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backbone router
A router that has an interface to the backbone, including area border routers
(ABR). A backbone router that has connections only to other backbone
routers also functions as an internal router.
backplane
The printed circuit board into which control and function processors on a shelf
are seated. The backplane serves two functions: distributes power to all
processor cards on the shelf, and supports the bus that transports data and
signaling between processor cards.
backplane bus
A cell-based 800 Mbit/s bus. The backplane bus allows each processor card
in a shelf to send data or signaling to any other processor card. There are two
backplane buses for each shelf: X and Y.
backplane control system (BCS)
The software system that manages the operation of the Nortel Multiservice
Switch 15000 and Multiservice Switch 20000 fabrics. The BCS controls the
fabrics on each processor card, allowing applications to send and receive
frames over the backplane X and Y fabrics. The BCS also monitors the state
of the fabrics to ensure that all cards can communicate. Lastly, the BCS allows
the operator to monitor and test the fabrics.
backplane fabric
A cell-based 56.3 Gbit/s fabric. The backplane fabric allows each processor
card in a shelf to send data or signaling to any other processor card. There
are two backplane fabrics for each shelf: X and Y.
backplane file system (BFS)
The file system that enables a processor card to access files on either the
active or standby control processor across the backplane.
backward congestion indication (BCI)
A bit in the Nortel Multiservice Switch packet header that indicates that
packets travelling in the opposite direction on the connection are encountering
congestion.
backward explicit congestion notification (BECN)
The bit in a frame relay header that indicates congestion in the path for the
direction opposite to the direction in which the frame is flowing.
backward resource management cell (BRM)
Forward resource management cells that the ABR destination device turns
around for delivery to the available bit rate source. See forward resource
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bandwidth-elastic connection
bandwidth-non-elastic connection
bandwidth management
Allows both connectionless and path-oriented traffic to share the same Nortel
Multiservice Switch trunk while ensuring that trunk bandwidth is not
oversubscribed to by circuits carrying voice and video traffic. Bandwidth is
reserved for the duration of a logical connection and can be partitioned among
services according to their priorities, minimizing the probability that voice and
video traffic is discarded.
bandwidth on demand (BWOD)
Capability enabling users to acquire varying amounts of bandwidth on
request.
bandwidth pools
In ATM traffic management, a method of reserving by service category a
percentage of link bandwidth (known as a bandwidth pool) for connections.
basic rate interface (BRI)
The interface between an ISDN subscriber and the ISDN switch (that is, the
local loop). The interface consists of two 64 kbit/s B-channels and one 16 kbit/
s D-channel.
basic virtual path terminator
A type of virtual path terminator that provides traffic management at the VC
level only.
Bc
BC
BCD
BCI
BCS
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Be
bearer channel (B-channel)
In ISDN connections, a 64 kbit/s digital bidirectional channel for carrying voice
and data traffic.
BECN
beginning of message (BOM)
The first cell in a series of cells that result from segmentation of higher-layer
packets or frames. The BOM cell marks the first cell in the cell series that
represents one packet or frame.
BFS
BGP
binary 3 zero substitution (B3ZS)
An encoding technique used to transfer bits over a DS3 line. B3ZS guarantees
1’s density by substituting a pattern of bipolar violations if three or more zeros
in a row are to be transported.
binary 8 zero substitution (B8ZS)
An encoding technique used to transfer bits over a DS1 line. B8ZS guarantees
1’s density by substituting a pattern of bipolar violations if eight or more zeros
in a row are to be transported.
binary-coded decimal (BCD)
1
A computer coding system that represents each decimal number with a
group of four binary digits (1s and 0s).
2
A component model data type.
bipolar violation (BPV)
A failure to follow alternate mark inversion coding. BPVs are intentionally
inserted in the bit stream using 1’s density techniques.
bit 7 stuffing
When a T1 or E1 time slot has all 0s, bit 7 (the least significant bit) is forced to
a 1.
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BITS
bit-transparent data service (BTDS)
Nortel Multiservice Switch application that transports continuous synchronous
data (isochronous) that has already been subjected to some form of encoding
across the network without interpretation. The continuous data stream is
broken into fixed sized cells and sent through the network.
block
A a series of contiguous memory locations. User data is stored in a block. All
blocks are assumed to be the same length, usually a binary (power of 2)
number of words. Memory blocks are linked together to form buffers.
BNX
The Bay Networks network element running hyperstream software.
BNX-Iwf
BNX interworking function. The set of capabilities that permits frame relay
services over IP connections between virtual routers on a Nortel Multiservice
Switch 15000 or Multiservice Switch 20000 node and a Bay Networks
network element running hyperstream software (BNX).
BNX-Iwf DLCI
BNX interworking function DLCI. A type of FrUni DLCI that is required for
interworking between the Bay Networks network element running
hyperstream software (BNX) and the Nortel Multiservice Switch 15000 or
Multiservice Switch 20000 node supporting frame relay over IP.
BOM
border gateway protocol (BGP)
Border gateway protocol (BGP) is an inter-autonomous systems routing
protocol for the Internet.
border node
A logical node at the edge of some kind of networking boundary, such as a
topology region, peer group, or cluster.
bootstrap router (BSR)
A dynamically elected router within a PIM domain that is responsible for
constructing the RP-Set and originating bootstrap messages.
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BPV
break-before-make rerouting
BRI
BRM
broadband inter-s interface (B-ICI)
An interface between public ATM networks.
broadcast
To send one or more messages to multiple addresses on one or more
networks.
BSR
BT
BTDS
buffer
A linked list of blocks. The blocks that make up a buffer are not necessarily
contiguous. Buffers are composed of multiple blocks when the user data does
not fit into a single block. The linkage of blocks to form a buffer is managed by
the queue controller.
buffer memory
building-integrated timing supply (BITS)
The most accurate and stable clock source within a physical structure. All
digital equipment in the structure receives timing reference from the same
master clock. BITS derives its signal from a stratum-3E or better reference
signal. BITS provides network clock synchronization through external timing
to the Nortel Multiservice Switch 7400, Multiservice Switch 15000, or
Multiservice Switch 20000 node.
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bundle
Grouping of one or more physical links using the formats and procedures of
the multilink frame relay (MLFR) standards. The bundle operates as a logical
interface function that emulates a single physical interface to the Q.922 data
link layer.
bundle link
A multilink frame relay (MLFR) sub-component that controls operation of one
of the bundle’s physical links.
burst tolerance (BT)
A characteristic of ATM usage parameter control applied to traffic defined
through traffic descriptor types 6, 7, and 8, and is based primarily on the MBS
value defined in parameter 3 for each of these types. BT is defined as MBS
minus 1 multiplied by the difference between the PCR and SCR cell intervals.
BT, together with SCR and the GCRA, determines the MBS that can be
transmitted at the PCR.
bus
The Nortel Multiservice Switch node bus.
bus control system (BCS)
The software system that manages the operation of the Nortel Multiservice
Switch node bus.
bus controller (BC)
A Nortel Multiservice Switch ASIC that allows a processor card to send and
receive data and to control information over a backplane bus. There are two
bus controllers for each processor card, one for each 800 Mbit/s bus.
bus mode
A property of a Nortel Multiservice Switch node that indicates the number of
backplane buses that are currently in service (for example, single-bus mode
or dual-bus mode).
bus tap
The interface between a processor card and the backplane bus. The bus tap
consists of a bus controller ASIC and some additional backplane interface
logic. There are two bus taps for each processor card.
bus terminator card
A printed circuit board that terminates backplane traces, thereby reducing
errors on the backplane buses by eliminating signal reflection. Each shelf
contains two bus terminator cards, one at each end of the backplane.
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BWOD
cable management area
One of the four divisions of the shelf. It allows orderly management of cables
and acts as an exhaust duct for hot air.
cache management system (CMS)
A feature that allows the user to configure the IP local cache table size.
CAC
call
Communication between two subscribers who are connected to endpoints of
the network.
call correlation tag (CCT)
An identifier, unique for each call, provided in the accounting record to
facilitate off-switch correlation of several records issued at different interfaces
in the network.
call establishment
Establishing a call between two access services across a network.
call management
The capability of the Nortel Multiservice Switch accounting system to prevent
the loss of accounting records by only accepting new SVC calls if the system
has enough resources to process the accounting records associated with the
SVC call. Call management is engineered for each logical processor.
call preservation
call redirection server (CRS)
Provides call redirection for DPRS services on Nortel Multiservice Switch
node-only networks. A CRS improves an application’s availability by
redirecting a call attempt that would otherwise fail because the destination
cannot be reached. Call redirection servers are located on function
processors that are spread throughout the routing identifier (RID) subnet in
the DPRS network.
call router (CR)
Provides the translation of a DNA to a routable identity.
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call server resource module (CSRM)
A DPN-100 resource module that is directly connected to and provides call
server functions for a Nortel Multiservice Switch network.
candidate bootstrap router (C-BSR)
A router configured to participate in a BSR election and acts as a BSR if
elected.
candidate rendezvous point (C-RP)
A router configured as a potential rendezvous point for a specified range of
multicast addresses.
CAR
card
An electronic circuit board. In Nortel Multiservice Switch documentation, card
usually refers to a processor card (either a function processor or a control
processor).
card port
An interface between the fabric card and the processor cards of the Nortel
Multiservice Switch 15000 or Multiservice Switch 20000 node.
Carrier’s Carrier
The feature, service or configuration that offers BGP/MPLS VPN services to
other service providers also offering BGP/MPLS VPN services to their end
customers. Also referred to as hierarchical BGP/MPLS VPNs.
Carrier’s Carrier customer edge router (CE’)
The Passport router that interfaces with the Carrier's Carrier PE router (PE')
and performs label distribution functionality between the customer carrier and
the Carrier's Carrier in order to utilize the MPLS VPN transit service provided
by the Carrier's Carrier. The CE' node also acts simultaneously as a PE router
to the end CE router of the customer carrier.
Carrier’s Carrier provider edge router (PE’)
The router that offers the Carrier's Carrier service to the CE' router.
CAS
1
2
CAW
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CBC
CBR
C-BSR
CC
CCITT
CCR
CCS
CCT
CDL
CDMA
CDV
CDVT
C-RP
CE
CE’
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cell
A small, fixed-length data unit, with associated control header (cell header),
that is transmitted across the network. Many cells can be required to carry a
complete message for a customer. The ATM cell is 53 bytes long.
cell delay variation (CDV)
The allowable variation in time that a cell can take to travel over a virtual
connection. Also, the measurable variation in the interval between ATM cells
arriving at a network element. The accumulation of this variation results in cell
clumping. Also known as cell delay variance.
cell delay variation tolerance (CDVT)
One of a set of ATM traffic characterization values. CDVT defines the
tolerance to cell clumping that results from the accumulating amount of cell
delay variation or “jitter” in the network or customer premises equipment
(CPE). CDVT is Nortel Multiservice Switch node-specific and is not part of the
ATM Forum specification.
cell header
Information wrapped within a cell that determines the destination of the cell
and carries sequencing and error detection information.
cell loss priority (CLP)
A bit located in the ATM cell header that identifies the priority of the cell as
eligible for discard at a point of congestion.
cell loss ratio (CLR)
The allowable percentage of cells that can be lost for a given traffic type. CLR
is the ratio between ATM cells transmitted by the source over a link and the
number of cells discarded by the destination due to congestion. CLR is a QOS
class parameter that defines the loss ratio that the service provider agrees to
over the lifetime of a connection.
cell queue controller (CQC)
The hardware chip that supports traffic shaping and usage parameter control
on ATM interfaces and connections, and that permits per-VC queuing. The
CQC ASIC defines the series of CQC ATM function processors as distinct
from other series of ATM function processors.
cell queue memory (CQM)
The RAM memory used by the cell queue controller (CQC). This memory is
used as buffer space for the link transmit queues, reserved space, and
connection space.
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cell switching
A hardware-based switching technology in which data entering the network is
broken down into one or more fixed-length cells. The cells are transported
independently through the network and reassembled at the destination.
cell transfer delay (CTD)
The time it takes a cell to travel from one end of a virtual connection to the
other. CTD is also defined as the measurable elapsed time between an exit
event at a measuring point (the source UNI) and an entry event at a measuring
point (the destination UNI). This measurement is the sum of the total inter-
node transmission delay and the total node processing delay between the two
measuring points.
central processing unit (CPU)
The main processing unit of a device that performs program sequencing and
arithmetic logic.
CES
channel
The smallest subdivision of a circuit that provides a single type of
communication service.
channel-associated signaling (CAS)
Signaling used in voice or modem connections in which specific bits in the
DS1 or E1 frame structure carry the ABCD signaling information for each
channel.
channel service unit (CSU)
A type of interface used to connect a terminal or computer to a digital medium.
A CSU also performs diagnostic and protective functions, such as providing a
keep-alive signal to maintain line synchronization.
child node
In an ATM PNNI network, a node at the next lower level of the hierarchy where
that node is contained in the peer group represented by the logical group node
currently referenced. The child node can be a logical group node or a physical
node.
child peer group
A child peer group of a peer group is any one group that contains a child node
of a logical group node in that peer group.
CID
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CIDR
CIR
circuit emulation service (CES)
A service that converts and transports data from one circuit format to another.
For example, a CES can convert DS1 circuit data to ATM cells at the ingress
node for transport over an ATM network, and then reconvert the data to its
original DS1 circuit format at the egress node.
Class A, B, and C (internetworking)
Address ranges for Internet addressing. These ranges are based on the first
eight bits of the address. Each range allows less of the whole address for host
addresses than the previous range.
•
•
•
A Range from 1 to 126. This class is used for networks that have up to 224
nodes, such as government agencies and major university systems.
Default address mask of 255.0.0.0.
B Range from 128 to 191. This class is used for networks that have up to
216 nodes, such as large corporations. Default address mask of
255.255.0.0.
C Range from 192 to 254. This class is used for smaller networks that
have fewer than 255 nodes, such as smaller colleges and businesses.
Default address mask of 255.255.255.0.
class of service (IP CoS)
A Nortel Multiservice Switch IP differentiated service feature that provides
limited IP traffic management.
classless inter-domain routing (CIDR)
An internetworking protocol that uses subnetwork masks other than the
defaults used for IP address classes. Defined in RFC1517 and RFC1518.
clock master
The bus tap in slot 0 or 15 that supplies clock signals for a backplane bus. This
term can also be used for the processor card that contains this bus tap.
closed user group (CUG)
A collection of users whose members are governed by certain rules of access
with respect to communication with each other, with members of other closed
user groups, and with the open part of the network. These rules maintain
security, prohibit unauthorized access. and provide logical partitioning of the
network for better access control.
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CLP
CLR
CLR alarm
An alarm that is issued subsequent to an associated SET alarm when the fault
condition no longer applies. These alarms have an activeListStatus value of
“CLR”.
cluster
cluster border node
Nortel Multiservice Switch nodes that reside on a cluster boundary, connected
by backbone-cluster border links to the backbone.
cluster node
Nortel Multiservice Switch nodes that reside within a cluster.
CMS
CNLS
CNM
CO
COI
code-division multiple access
A method of allowing multiple users to access the same system by assigning
them different digital codes which they can use to decode their desired
narrowband information from the stream's wideband composite signal.
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cold standby
Applications and features that operate with a standby instance that is not
synchronized with the active instance of the software. During an equipment
switchover, cold standby applications incur longer outages than hot standby
and warm standby applications, and all connections must be re-established.
COM
Comité Consultatif International Télégraphique et Téléphonique (CCITT)
A European standards body now known as ITU-T.
command area
An adjustable segment of a window where you enter and review commands.
The command area contains two fields: a command (input) field and a history
field.
command file
A set of instructions stored as a macro. When the command file is executed,
all instructions or commands in that file are performed automatically.
command line interface
An area on a terminal screen that allows you to enter instructions from the
keyboard and then execute those instructions.
committed burst size (Bc)
The maximum amount of data (in bits) that a network agrees to transfer under
normal conditions over a measurement interval.
committed information rate (CIR)
The rate (in bit/s) at which the network agrees to transfer information over a
connection. It is related to committed burst size (Bc) and measurement
interval (T) as CIR = Bc/T.
common header
A small Nortel Multiservice Switch node-specific common frame header that
is appended to the front of frames and cells that are routed between Nortel
Multiservice Switch nodes.
common channel signaling (CCS)
A signaling system in which signaling control data for all channels on a facility
is carried on a single separate channel in the form of a data protocol. For
example, the control signals for 30 voice channels are carried on an ISDN
PBX trunk, and the data channel (D-channel) is carried in one of the remaining
channels.
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common part convergence sublayer (CPCS)
A sublayer of the AAL-5 layer.
common queuing
An ATM queuing structure in which traffic from two or more connections is
placed on a single queue during node congestion. Traffic is processed in
round-robin fashion within the common queue. Compare with PHB
common transmit clock (CTC) mode
An IMA configuration in which the same transmit clock is used for all physical
links in the IMA group. This configuration contrasts with independent transmit
clock (ITC) mode.
community of interest (COI)
The source and destination of communications traffic. Two common COIs
referred to are as follows:
1
2
A local COI refers to the traffic entering on access ports of a Nortel
Multiservice Switch node that is destined for another port on the same
node.
A network COI refers to a matrix of inter-node traffic in the network. For
each node in a network, the matrix has an entry for the volume of data
originating from that node and terminating on the other nodes in the
network.
component
Used by the network operator or administrator to control Nortel Multiservice
Switch software, hardware, capabilities, and access services. Each
component represents some part of the Multiservice Switch network—a
service, a piece of software, or a physical hardware element. Standardized
and organized in a highly structured fashion, components provide the model
for operator interaction with Multiservice Switch. All commands for
provisioning, monitoring, and maintenance are addressed to components.
component administration system (CAS)
The command and control system that processes network management
requests by passing them to the appropriate components for action and
returns the results to the source of the request. CAS also provisions and
creates components on the Nortel Multiservice Switch node. In addition, when
working with the network management interface system (NMIS), CAS
provides the provisioning view for external network management systems.
component description language (CDL)
A proprietary data modeling language for Passport managed objects. CDL is
encoded within FrameMaker .cdf files or ASCII .cdl files.
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component instance
When more than one of a component type exists, they are differentiated by an
instance value. The instance value is information (such as a decimal or a
string) appended to the component type.
component model
An OSI-like management model describing Nortel Multiservice Switch nodes
in terms of a set of components arranged into hierarchies. Components
contain attributes that are arranged in attribute groups. Components support
verbs that take options. A verb applied to a component can produce
responses. Components can also produce asynchronous responses, such as
alarms. The component model is supported over the local, Telnet, Ssh, and
FMIP NMIFs. It is indirectly supported within the Multiservice Switch
enterprise SNMP MIB.
component type
The part of the component name that identifies the component being referred
to. For example, FrameRelayUni is the component type of the component
name FrameRelayUni/4.
congestion state
An indication of the degree of congestion of a memory entity such as a queue
or free list. On ATM FPs, there are four congestion states, where 0 is the most
congested and 3 is the least congested. When a memory entity is in
congestion state x, all data of discard priority greater than x is discarded.
congestion control (CC)
ATM mechanisms that detect, prevent, and correct traffic congestion.
conjugate-structure, algebraic-code-excited linear prediction (CS-
ACELP)
An 8 kbit/s compression algorithm used to encode voice data, based on ITU-T
recommendation G.729.
connection
A channel or path between two network entities. The channel or path can be
either physical or virtual. A network entity is any system or subsystem that is
attached to the network medium.
connection address resolution (CAR)
The protocol by which a data network address is resolved into a routable
destination on the network for the purpose of establishing a call connection.
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connection admission control (CAC)
A preventative ATM traffic management strategy through which Nortel
Multiservice Switch nodes evaluate a connection request based on the traffic
characteristics of both established connections and the requested connection.
The request is accepted if the new connection does not jeopardize the QOS
of established connections.
connection bandwidth control (CBC)
Connection bandwidth control guides the response of ATM connections to
changes in bandwidth available over an ATM link.
connection recovery
A process of finding an alternate route for a failed connection that would have
been cleared back to the end-user. In connection recovery, the incumbent
connection segment is released before the establishment of an alternate
connection segment. Connection recovery is also known as hard rerouting
and break-before-make rerouting.
connection segment
A portion of an end-to-end connection or the entire end-to-end connection,
spanning a series of intermediate nodes across a PNNI network.
connection scope
The PNNI routing level above which the network cannot route calls.
connection scope selection information element (CSS-IE)
A signaled information element that is used in ATM anycast call requests.
CSS-IE in the call setup message permits the calling endstation to constrain
a point-to-point connection request using the ATM anycast capability to group
members within a specified level of routing hierarchy.
connection trace
A control plane mechanism that determines the physical nodes and physical
links traversed by existing connections that have already been established.
connectionless routing (CNLS)
A point-to-point routing service where a message’s path through the network
is not specified during the call establishment phase. Instead, the path for each
data unit (a frame or cell) of a message is calculated independently and
dynamically. Each path is based on the destination address of the frame,
current network topology, and available bandwidth. Connectionless routing
features a high degree of robustness and reliability, since data can be easily
steered away from failed or heavily congested facilities.
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connection-oriented routing (CO)
A routing service in which the path used by the frames or cells is determined
when the connection is set up and remains fixed for the duration of the
connection (barring network problems). Each path is set up on the nodes of
that path and each packet needs a minimum of routing information.
connection preservation
The process of maintaining a connection over a sequence of potentially
disruptive events such that the connection does not need to be reestablished
when that sequence of events is complete.
Also known as call preservation.
constant bit rate (CBR)
An ATM Forum UNI 4.0 quality of service (QOS) class. This QOS class
defines a static bandwidth that is continuously available for the duration of a
connection. Corresponds to UNI 3.0/3.1 QOS class 1 and to Nortel
Multiservice Switch constant bit rate QOS class.
Networks use CBR for voice, video, and telemetry services that need carefully
metered transmission rates. In this sense, CBR emulates individual private
line service. CBR avoids disagreeable “glitches” in service quality that result
from data rate variance and data losses.
continuation of message cells (COM)
All cells in a stream between the beginning of message cell and the end of
message cell, all of which belong to a series of cells that result from
segmentation of higher-layer packets or frames.
control plane (C-plane)
Defines all aspects of the management and control of frame relay. The local
management interface (LMI) is the interface to the C-plane. It uses procedures
defined in
•
Frame Relay User-to-Network Interface With Extensions, document
number 001-208966 (available through Nortel Networks)
•
•
ANSI T1.617 Annex D
ITU-T Q.933 Annex A
For more information, see NN10600-900 Nortel Multiservice Switch 7400/
15000/20000 Frame Relay Technology Fundamentals.
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control plane protection (CPP)
An IP feature designed to protect the Nortel Multiservice Switch against
certain denial of service (DoS) attacks on the control plane. This control plane
can be defined as all packets that have locally destined IP addresses within a
VR, VCG, RTR, or VRF address space and are terminating on the
Multiservice Switch node.
control processor (CP)
A type of processor card optimized to support the software that performs
complex, memory-intensive processes. Among other things, these processes
parse operator commands, and modify and display provisioning data. The
control processor also supports the administration interfaces for the Nortel
Multiservice Switch node. Each node must have an active control processor
and can also have (for redundancy) a standby control processor. Each control
processor contains the disk, a DCE V.24 interface, and an Ethernet interface
to manage the node.
control processor (CP) switchover
The process of the standby CP becoming active. This process can occur upon
CP failure, restart of the active CP, a manual reset of the CP, or when a
switchover is invoked manually using the “Switchover Lp” command.
convergence sublayer (CS)
A sublayer of an ATM adaptation layer.
Coordinated Universal Time (UTC)
A time standard that Nortel Multiservice Switch software uses for establishing
network time, that is equivalent to Greenwich Mean Time (GMT). GMT is the
time at the Greenwich meridian (0 degrees longitude).
cooling unit
The cooling unit is a hardware component of a Nortel Multiservice Switch
node. It contains a forced-air cooling system that ensures adequate cooling of
the processor cards. For more information, see NN10600-170 Nortel
Multiservice Switch 7400 Hardware Description or NN10600-120 Nortel
Multiservice Switch 15000/20000 Hardware Description.
core networking
Encompasses the three Nortel Multiservice Switch networking systems:
PORS, and DPRS.
CoS
CP
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CPP
Customer premises equipment.
CPCS
CPE
CPeD
C-plane
CQC
A control processor with external (BITS) DS1 timing support.
CQC function processor
A type of Nortel Multiservice Switch ATM node function processor that uses a
cell queue controller (CQC) ASIC. This type of function processor was the
original ATM FP on Multiservice Switch nodes.
CQM
crankback
A mechanism in ATM networking that partially releases a connection setup in
progress when that setup request encounters a failure in the network. This
mechanism allows ATM routing protocols to perform alternate routing.
CR
critical IP address
An IP interface on the local router. If the VRRP virtual router configuration
includes a critical IP interface address, a change in state to that IP interface
causes a role switch in that VRRP virtual router.
CRC-4
CRC-6
A cyclic redundancy check pattern used on an E1 line.
A cyclic redundancy check pattern used in extended superframe (ESF) mode
on a DS1 line.
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cross-net polling
The process of periodically exchanging a status message across the subnet
between the two end points of a PVC. This message indicates the status of
the source to the destination.
CRS
CS-ACELP
CSRM
CSS-IE
CSU
CTC mode
CTD
CUG
cumulative administrative weight (CAW)
Sum of the connection segment costs across the rerouting domain.
current cell rate (CCR)
The cell rate at which ATM elastic connections are operating when they are
not running at full capacity (in a reduced bandwidth state). When an elastic
connection is operating at full capacity, its CCR is equal to its equivalent cell
rate (ECR).
customer edge device or router (CE)
A router or device that is part of a customer network and that interfaces to a
provider edge (PE) router.
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customer identifier (CID)
The customer identifier is used in customer network management (CNM) to
limit the user’s access to components that belong to the same customer
identifier. A CNM operator can send commands only to components
provisioned with the same CID as the operator. A CNM operator receives only
data collection system (DCS) data, such as alarms, that is generated by
components provisioned with the same CID as that of the operator. The
special CID of 0 is reserved for the network owner, known as the network
manager (Netman). A CID of zero is required to provision the overall network.
customer network management (CNM)
Allows virtual private network (VPN) user access to VPN-specific information,
such as real-time alarms and the use and status of VPN network components
and shared components.
D-channel
D4
One of the framing patterns for DS1, in which there are 12 frames for each
data circuit-terminating equipment (DCE)
In data communications, the equipment at the network side of a subscriber
link that provides both interface control and the means of digital transmission
between user premises and the network nodes.
data collection system (DCS)
A software system that collects various types of management data (such as
alarms, accounting records, logs, state change notifications, and traps
information) and distributes it as requested.
data encryption standard (DES)
A symmetric encryption algorithm standardized by the National Institute of
Standards and Technology.
data link connection identifier (DLCI)
Ten bits within the two address octets of a frame relay address header that
carry information used to locally identify the virtual circuits or permanent
virtual circuits. For more information, see NN10600-900 Nortel Multiservice
Switch 7400/15000/20000 Frame Relay Technology Fundamentals.
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data flow preservation
The process of maintaining uninterrupted data flow over a sequence of
potentially disruptive events. Connection preservation is implied whenever
data flow is preserved. Data flow preservation does not guarantee that data is
never discarded (for example, due to either congestion or error conditions).
data link control (DLC)
An interface that provides logical link control connection services.
data link switching (DLSw)
A forwarding protocol for wide area network support of the NetBIOS protocol.
data manipulation engine (DME)
The data manipulation engine (DME) is the base service that provides
capabilities for moving data frames to/from link interfaces and between
function processors within a Nortel Multiservice Switch node. It is designed to
provide protocol-based applications with the capability of performing
operations on data frames. Such operations are packet header manipulation,
packet retransmission, timing events, and queuing.
data network address (DNA)
A DNA is an identifier given to applications in many data networks. This
address is used as the fundamental identifier for setting up a virtual circuit
between data networks.
data packet network
A standards-based data networking system for interconnecting diverse host,
application, and end-user environments. The system gives organizations the
ability to choose the best solutions for data networking. DPN-100 addresses
the needs of organizations for reliable multi-protocol data services, such as
frame relay, SNA, and X.25, at speeds up to T1/E1. It supports a wide range
of physical interfaces including V.24, V.35, V.36, X.21, G.703, and token ring.
The highest possible availability, 99.999%, is achieved through networking
features, built-in redundancy, and a modular design.
data path object (DPO)
A data path object is a C++ object that processes frames at the interrupt level
on a Nortel Multiservice Switch card. A frame processes by passing through
a chain of DPOs; each DPO returns the ID of the next DPO in the chain. You
can configure a DPO to be addressable module-wide.
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data path object environment
A data path object environment is one of the two programming environments
that are extensions of the operating system. The data path object environment
supports the functions of Nortel Multiservice Switch network services, that is,
functions that associate with data path processing.
data service unit (DSU)
A type of interface used to connect a terminal to a digital medium. In most
cases, it is used in conjunction with a CSU. Refer to channel service unit
(CSU) (page 27) for details.
data terminal equipment (DTE)
The name used to designate the user equipment on a subscriber link.
data type
A division of information with common qualities that affect their representation
and semantics (for example, numbers or strings). Data types are used to
represent values in component instances, component attributes, verb options,
response attributes. They are used as index values within replicated, vector,
and array attribute types. The component model supports the following data
types and variations: array, ASCII string, binary-coded decimal (BCD),
component name, compound, dashed hex string, decimal, enumeration,
extended ASCII string, hex number, hex string, IP address, link, list, long, null,
replicated, integer sequence, set of bits, signed, time, fixed-point decimal,
vector, and wild-carded BCD.
For more information on each attribute type, see the appendix on attribute
types in NN10600-060 Nortel Multiservice Switch 7400/15000/20000
Component Reference.
DBNL
DBR
DCE
DCS
DE
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DR
default gateway
The gateway used to reach a destination if no other route is known or
provided.
Defense Network Secure Information Exchange (DNSIX)
A protocol defined in RFC 1038 and RFC 1108 for passing confidential data
securely over a network.
delta channel (D-channel)
A bidirectional channel, also known as the D-channel, used to carry call
control messages and signaling information over ISDN links.
designated router (DR)
When a LAN has multiple multicast routers attached, one of the routers is
elected as the router designated to forward the multicast traffic.
designated transit list (DTL)
A list of node and link identifiers that completely specify a path across a single
PNNI peer group. Link identifiers are optional.
device alarm
An alarm that originated from a device (for example, a Nortel Multiservice
Switch node).
DGCRA
dial backup network link (DBNL)
A type of dial-in DPN gateway providing connectivity when a dedicated
connection breaks.
dial-in DPN gateway
A connection made by modem between a DPN module and a Nortel
Multiservice Switch node. The network link type is dial backup.
DiffServ
A Nortel Multiservice Switch IP differentiated service feature that provides IP
traffic management.
DiffServ domain
A group of virtual routers that are using the same per-hop-behavior
(page 101) definitions to apply differentiated services to IP traffic.
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differentiated services code point
A 6-bit field in an IP packet header that is used for specifying differentiated
service parameters for the IP packet.
Digital Private Network Signaling System No 1 (DPNSS 1)
A common-channel signaling protocol intended for use between PBXs in
private networks through time slot 16 of a 2.048 Mbit/s digital transmission
system. Similarly, it can be used through time slot 23 of a 1.544 Mbit/s digital
transmission system.
DIN
Deutsche Industrialische Norm. A set of standards for electronic and industrial
products that originated in Germany.
Dijkstra’s algorithm
An algorithm that is sometimes used to calculate routes in an ATM network,
given a link and nodal state topology database.
direct memory access (DMA)
A method of transferring data to or from memory without having to use the
CPU, thus improving the overall speed of the system.
discard eligibility (DE)
A bit in the frame relay header. A frame is marked with the DE bit to indicate
that, in times of congestion, the frame is to be discarded before frames without
the DE bit set. This bit is set either by the user or the network.
discard priority (DP)
Discard priority refers to the importance of a frame or cell. The Nortel
Multiservice Switch system has 4 discard levels, where 0 is the most important
(last to be discarded) and 3 is the least important (first to be discarded).
Discard priority 0 is reserved for Multiservice Switch control traffic, leaving
three discard priorities for user traffic.
DLCI
DLSw
DMA
DME
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DNA
DNSIX
domain
domain-based rerouting (DBR)
An ATM Forum standard protocol that enables the PNNI network to employ a
rerouting mechanism that protects a connection segment within one or more
local rerouting domains.
double-ended accounting
Accounting records are generated at both the ingress and egress ends of the
connection. This option is available for both frame relay and ATM accounting
features. BothEnds is another term for a double-ended accounting record for
frame relay accounting. Double-ended accounting is recommended for ATM
accounting over single-ended accounting to ensure the records reflect the
actual amount of data transported from end to end.
downspeeding
In bit-transparent data service (BTDS) software, the capability of decreasing
the data rate by adjusting the physical clock speed of the line in response to
congestion.
DPN
DPN gateway
A Nortel Multiservice Switch node-to-DPN connection. Its provisioning is
similar to that of a Multiservice Switch trunk.
DPN routing
DPNSS 1
DP
DPO
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DPRS
DRAM
Dynamic random access memory.
drop precedence (DP)
Drop precedence refers to the importance of an IP packet. A drop precedence
value is assigned to a packet to control its loss sensitivity relative to other
packets when they are placed on the same queue. Generally, a drop
precedence value of low indicates the packet is less likely to be discarded
when the queue is congested. This traffic has a higher probability of being
forwarded. Similarly, a drop precedence value of high indicates the packet is
more likely to be discarded when the queue is congested. This traffic has a
lower probability of being forwarded. The actual loss sensitivity of packets
depends on the discarding mechanism at the queue.
DS0
DS1
The 64 kbit/s line standard format for North America as defined by the ITU-T.
The 1.544 Mbit/s interface defined in ITU-T G.703. Consists of a framed
pattern of twenty-four 64 kbit/s time slots.
DS1c
DS3
A digital signal level having a transmission rate of 3.152 Mbit/s carrying
48 DS0s plus overhead bits.
The 44.736 Mbit/s line standard format in North America as defined by the
ITU-T. This is the format used to carry information over the T3 trunk.
DSCP
DSU
DTE
DTL
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DTL originator
The first lowest-level node within the entire PNNI routing domain to build the
initial DTL stack for a given connection.
DTL terminator
The last lowest-level node within the entire PNNI routing domain to process
the connection (and thus the DTL for the connection).
DTMF
dual-bus mode
A configuration in which both backplane buses are available to carry cells
between operational cards.
dual fabric mode
A configuration in which both backplane fabric cards are available to carry
cells between operational cards.
dual-FP line APS
A type of implementation scheme that uses two optical interface cards to
provide SONET or SDH line automatic protection switching. Dual-FP APS
allows equipment sparing for optical interface cards.
dual leaky bucket
dual tone multi-frequency (DTMF)
A signalling method that uses specific pairs of frequencies within the voice
band for signals.
dynamic generic cell rate algorithm (DGCRA)
A version of the GCRA. DGCRA uses information supplied by ABR.
dynamic packet routing system (DPRS)
A connectionless routing system for delay-sensitive and high-throughput
variable bit rate traffic. DPRS carries data traffic such as frame relay and all
DPN-100 services such as X.25.
E1
The 2.048 Mbit/s interface defined in ITU-T G.703. Usually consists of a
framed pattern of thirty-two 64 kbit/s time slots.
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E3
The 34.368 Mbit/s interface defined in ITU-T G.703 and G.704.
E.164
The ITU-T recommended numbering plan for ISDN that includes the
numbering plan for public switched telephone networks.
early packet discard (EPD)
EPD is a feature that applies a more stringent discard policy to the first cell of
an AAL-5 frame than it does to subsequent cells. This reduces the number of
incomplete frames in the network and thereby increases the throughput.
EAP
EBGP
EBR
1
2
echo cancellation
A technique in voice networking that allows for the isolation and filtering of
unwanted signal energy caused by echoes from the main transmitted signal.
ECR
edge-based rerouting (EBR)
Edge-based rerouting refers to procedures used in a PNNI network to recover
and optimize active point-to-point SVC, SVP, soft PVC, and soft PVP
connections.
EFCI
EG
EGP
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egress accounting
A method of collecting information based on customer use of network
resources. The information is used by the service provider to develop billing
policies and quality of service parameters. As the name implies, this
information is collected at the exit (egress) points of the network for each
frame relay data link connection (DLC).
egress node
The last Nortel Multiservice Switch node that processes the packet as it
traverses the Multiservice Switch network; that is, the node from which the
packet exits the Multiservice Switch network.
egress protocol
The egress protocol synchronizes the accounting meters at the opposite ends
of the connection and facilitates the exchange of data collected by the
accounting meters.
egress traffic
Egress traffic refers to the traffic exiting from a Nortel Multiservice Switch
network through an access point.
EIR
elastic connection
An ATM connection type that is able to respond to changes in bandwidth over
an ATM link through a decrease or an increase in its contracted data rate.
EM
emission priority (EP)
Traffic management mechanism used to handle delay requirements of
different types of traffic. Emission priority grading is implemented in three
emission queues, interrupting, high, and normal, which are serviced in that
order. The interrupting queue is typically used for CBR traffic, such as voice
and BTDS. The high and normal priority queues are used for VBR traffic, such
as frame relay. This queue arrangement allows delay-sensitive cells, such as
voice and video, to interrupt the transmission of long data frames, such as
frame relay. (In ATM FPs, there is no interrupting queue, since multiplexing is
already occurring at the cell level. The queues are known as high, medium,
and normal.)
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A class scheduler uses emission priority to determine relative importance
between service classes for the purpose of determining which service class
data is forwarded to the next queue.
end of message (EOM) cell
The last cell in a series of cells that result from segmentation of higher-layer
packets or frames. The EOM cell marks the last cell in the cell series that
represents one packet or frame.
endpoint (EP)
The software managing the subscriber access point. The endpoint can
include the software for the access service, the virtual channel or path, or the
logical connection.
end system
A system on which connection termination points are located.
end-to-end connection
The entire connection within the PNNI network from the PNNI source node to
the PNNI destination node.
enterprise module (EM)
The root-level component of Nortel Multiservice Switch node. Its instance
value is the node name.
entry border node
The node that receives a call over an outside link. This node is the first within
a peer group to see the call.
EOM
EP
1
2
EPD
equipment sparing
Switching service functionality from failed hardware to equivalent standby
hardware. For CPs and FPs, one-for-one sparing enables a spare processor
card to stand by for an equivalent single main processor card. One-for-n
sparing enables a spare processor card to stand by for “n” main processor
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cards. One-for-n FP sparing requires a sparing panel and only applies to
equivalent bit rate (EBR)
The bandwidth (in bit/s) that the network reserves for a FR-ATM connection.
The EBR or requested bandwidth computation for each connection request
determines the CAC mechanism.
equivalent cell rate (ECR)
The bandwidth (in cell/s) that the network reserves for a particular ATM
connection.
ER
ESD jack
A jack located on the Nortel Multiservice Switch node for plugging in an
antistatic wrist strap to protect the hardware against electrostatic discharge.
ESF
Ethernet
A physical and data link layer protocol that follows the IEEE 802.3 standard or
the related Xerox, Digital, and Intel Ethernet standard.
Ethernet address
A 48-bit media access layer (MAC) address composed of an assigned six-
octet manufacturer’s code and a unique number (such as a serial number)
provided by the manufacturer.
ETSI
European Telecommunications Standards Institute. A telecommunications
standards body.
ETSI QSIG
European Telecommunications Standards Institute Q interface signaling. A
common channel signaling protocol supported by the Nortel Multiservice
Switch Voice Networking service.
European digital subscriber signaling system number one (EDSS1)
A common channel signaling protocol supported by the Nortel Multiservice
Switch Voice Networking service.
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excess burst size (Be)
The amount of data (in bits) that a network agrees to transfer over a measured
interval if network bandwidth is available.
excess information rate (EIR)
The sustainable rate of data transfer in excess of CIR that the network delivers
if there is available bandwidth. It is related to excess burst (Be) and
measurement interval (T) as EIR = Be/T.
exit border node
The node that progresses a call over an outside link. This node is the last
within a peer group to see the call.
explicit forward congestion indication (EFCI)
An indicator that an ATM network element can set in a cell header to indicate
pending or current network congestion. End system applications can read this
indicator and reduce transmission requirements, which in turn reduces
network congestion over time. EFCI is a reactive traffic management strategy.
Not all applications can read the EFCI and respond accordingly.
Also, a function of ABR through which nodes indicate the presence of local
congestion by setting a bit in traffic cells.
explicit rate (ER)
A function of ABR whereby nodes deposit an explicit cell rate offer in a BRM
cell based on the current rate and locally determined congestion.
export policy
A collection of rules that govern the distribution of route information. These
policies are used by the BGP, EGP, OSPF, and RIP route management
protocols.
extended superframe (ESF)
One of the framing patterns for a DS1 line consisting of 24 frames for each
exterior
In PNNI networking, a term that indicates that an item (such as a link, node,
or reachable address) is outside of a PNNI routing domain.
exterior link
A link that crosses the boundary of the PNNI routing domain. The PNNI
protocol does not run over an exterior link.
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exterior reachable address
An address that a node can reach through a PNNI routing domain but that is
not located in that PNNI routing domain.
external address plan (EAP)
An address plan that is not the Nortel Multiservice Switch internal address
plan. Examples of EAPs are a DPN internal address plan and an IP address
plan.
external border gateway protocol (EBGP)
BGP configuration in which sessions are established between routers in
different autonomous systems (ASs). See also border gateway protocol
external gateway (EG)
A connection to a non-Nortel Multiservice Switch external module (for
example, a connection to a DPN-100 module).
exterior gateway protocol (EGP)
An IP routing protocol that operates between autonomous systems on the
Internet. BGP-4 is replacing EGP.
external routing protocol
A routing protocol from another network. Routing of external protocols is done
either natively or using encapsulation. External protocols are routed natively
when the packet is routed directly according to the address contained in its
header. Encapsulation is used to completely envelop the external protocol
within a Nortel Multiservice Switch packet, using it for making routing
decisions.
fabric card
The circuit pack that performs the cell-switching activities between the
processor cards of a Nortel Multiservice Switch 15000, or Multiservice
Switch 20000 node.
fabric port
An interface to the fabrics of a Nortel Multiservice Switch 15000, or
Multiservice Switch 20000 node.
facsimile handling
The handling of in-band facsimile or modem data dynamically. On detection of
a facsimile or data call, echo cancellation is disabled and the voice
compression rate is adjusted to allow the facsimile or data information to be
transported to its destination.
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fair buffer allocation (FBA)
Guarantees that connections or classes receive a fair portion of the total
available cell buffers in a function processor.
FAS
fast management information protocol (FMIP)
The proprietary fast management information protocol (based on OSI/ASN.1
principles) implemented between a Nortel Multiservice Switch node and
Nortel Multiservice Data Manager workstation, to manage the node.
FAX handling
fax idle suppression (FIS)
A function performed by Nortel Multiservice Switch nodes when processing
facsimile transmissions, which saves bandwidth by not transmitting the idle
portions between data bursts. During a typical facsimile transmission, FIS can
reduce bandwidth use by as much as 20 percent in the sending direction and
80 percent in the receiving direction.
fax relay
A modulation/demodulation technique used by the voice transport service for
transmitting facsimile traffic across a Nortel Multiservice Switch network. The
types of modulation supported are based on ITU-T recommendations V.27 (up
to 4.8 kbit/s) and V.29 (up to 9.6 kbit/s). Fax relay is only supported on MVP-
E FPs.
FBA
FCI
feature
Nortel Multiservice Switch applications consist of features (for example, frame
relay UNI is a feature of the frame relay application). Each processor card is
provisioned to run a set of features.
feature list (FL)
The list of provisionable features that can be loaded onto a processor. The
feature list is a provisionable attribute of a logical processor type.
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FECN
file
A set of related records that are treated as a unit for the purposes of storage
and retrieval.
file prober
Software residing on the Nortel Multiservice Data Manager workstation that
uses FTP to transfer accounting data from the Nortel Multiservice Switch node
to the host computer.
file transfer protocol (FTP)
A TCP/IP protocol used to transfer files across an internet. See also Internet
filter
A subroutine for discriminating among packets. Filters are used to decrease
traffic or improve security over network interfaces.
filtering
In the context of using commands such as list, display or find, filtering is an
operation that decreases the number of components targeted by a command.
FIS
FL
FLM
FMI
FMIP
FMIP enclosed
Format type associated with Nortel Multiservice Switch system accounting
and statistics records. FMIP enclosed accounting and statistics records are
raw data records that are enclosed in FMIP headers and trailers.
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foreign address
An address or address prefix that does not match the summary addresses
provisioned on any given node.
forward congestion indication (FCI)
A bit in the Nortel Multiservice Switch common header set to indicate that
congestion was experienced by packets travelling through the Multiservice
Switch network. Congestion in the subnet and at the access is indicated by
BCI/FCI bits. The frame relay service at the node evaluates frames from the
subnet for BCI/FCI bit indications, and based on this, sets the appropriate
BECN/FECN bit on the frame sent to the user.
forward explicit congestion notification (FECN)
The FECN bit is used in the frame relay header of a frame to warn the
receiving-end device that the frames it is receiving (traveling in the same
direction) have encountered congestion or congested resources.
forward resource management cell (FRM)
Resource management cells that an ABR source sends to its destination. See
FP
frame
A variable length data unit, with an associated control header, that is
transmitted across the network. The frame header determines the destination
of the frame and carries sequencing and error detection information. Many
frames are required to carry a complete document or message.
frame alignment signal (FAS)
A sequence of signal bits used for synchronizing E3 frames.
frame-cell trunk
The transport mechanism used by Nortel Multiservice Switch trunks to carry
both frame and cell traffic on a frame-based interface.
HDLC mode is a provisionable mode in which a frame-cell trunk can operate
and use HDLC framing.
Interrupting mode is a provisionable mode in which a frame-cell trunk can
operate and use a modified HDLC-based framing. Interrupting mode allows
highest priority data to interrupt traffic less sensitive to delay or traffic with a
lower emission priority.
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frame link monitoring (FLM)
Provides the ability to distinguish between physical line failure and customer
premises equipment failure in the case of a system failure at the access to a
Nortel Multiservice Switch frame relay node.
framed protocol
A set of formal rules describing how to transmit frames. HDLC framing uses a
standard protocol for the sequential transmission of individual frames.
Interrupting framing uses a modified-HDLC format that allows voice cells to
interrupt the transmission of data frames, transmit the voice cell, and continue
transmitting the data frame.
Framer
The Framer component controls link layer framing for application components
sending and receiving data on a link interface. For frame relay applications, it
is also through Framer that an application component is associated with a
specific hardware link interface.
frame mode information (FMI)
The system responsible for maintaining the Nortel Multiservice Switch node-
to-node connections. For example, FMI supports the following connections:
Multiservice Switch node-to-Multiservice Switch node, Multiservice Switch
node-to-DPN-100 access module, Multiservice Switch node-to-DPN-100
resource module.
frame relay IP server
A logical representation that allows multiple IP-enabled FrUnis on the same
function processor to share a single protocol port on the virtual router.
frame relay multiplexor/demultiplexor
A Nortel Multiservice Switch component that can distinguish traffic from
multiple frame relay peers for distribution to multiple applications in a
Multiservice Switch node.
frame relay managed cut-through switching (MCS)
A feature that provides bidirectional, point-to-point virtual connections
between Nortel Multiservice Switch nodes at a specific quality of service
(QOS). The MCS connection is a switched path that provides many-to-one
multiplexing of connections for a data service.
frame relay service (FRS)
A streamlined ISO data link layer protocol. A frame relay network supports
only core communications functions (such as transparency, multiplexing, and
orderly delivery). This simplified processing (as opposed to traditional packet
data protocols) permits higher speeds and lower delays for a given processing
capability. Simplification is made possible by the assumed use of improved
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transmission facilities (high-quality digital facilities), which are affected by far
fewer transmission errors. Furthermore, many functions such as sequencing
flow control and retransmission are performed by end user equipment.
Frame relay-to-ATM interworking function (FR-ATM IWF)
A Nortel Multiservice Switch frame relay service that provides interworking
functions between frame relay PVCs and ATM PVCs using AAL-5.
FR-ATM accounting
An accounting service that collects usage information (byte and frame counts)
on FR-ATM connections. Service providers can use this information to bill their
customers, or for test, statistics, network engineering, and planning purposes.
FR-ATM gateway
An application of the FR-ATM interworking service that converts frame/cell
traffic to and from ATM cell traffic. The FR-ATM gateway provides a frame
relay interface (either UNI or NNI) that converts frame relay traffic coming in
from its link into cells leaving the node at an ATM interface. In the other
direction, the gateway converts cell traffic coming into the node at the ATM
interface to frame relay traffic going out on the frame relay UNI or NNI. The
FR-ATM services frame relay traffic originating across the frame/cell subnet.
FR-ATM interworking service
The FR-ATM interworking service allows the carriage of frame relay traffic
over an ATM networking and transport infrastructure. It maps frame relay
permanent virtual circuits (PVCs) to and from ATM PVCs to provide
connectivity between frame relay CPE and ATM-capable CPE. The FR-ATM
interworking service comprises a core frame relay UNI/NNI service and an
interworking function.
The FR-ATM interworking supports the application of the FRF.8 standard for
service interworking (SIWF) and the FRF.5 standard for network interworking
(NIWF).
free list
The part of the shared memory that is currently unused and available for data
arriving into the FP card.
free list size
The number of blocks that currently make up the free list.
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free list threshold
A free list threshold is a specific number of blocks used in the determination
of the congestion state of the free list. A free list can define several thresholds.
As the free list size crosses each threshold, the free list enters a more severe
congestion state. For example, ATM FPs define three free list thresholds. The
free list at its maximum size starts off in congestion state 3; and as it is
depleted and falls below the first threshold, it enters congestion state 2.
FRIP
FRM
FRS
FTM
The Nortel Multiservice Switch traffic management system. It detects
congestion and reports it to the service (frame relay, for example).
FTP
full FMIP
Format type associated with Nortel Multiservice Switch system accounting
and statistics records. For full FMIP accounting and statistics records, each
field is completely encoded in FMIP format.
function processor (FP)
A type of processor card that supports physical interface connections to
subscriber lines and network trunks. It is optimized to support the software
that performs the real-time functions associated with the forwarding and
routing of frames. Different types of FPs support different types of physical
interfaces, such as DS1, E1, V.35, and V.11 access and trunks. See also
G.711
G.729
ITU-T standard related to pulse code modulation (PCM) of voice frequencies.
ITU-T standard related to coding of speech at 8 kbit/s using conjugate-
structure algebraic-code-excited linear-prediction (CS-ACELP).
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gateway
1
2
3
4
5
6
7
8
gateway identifier (GID)
An integer that uniquely identifies an X.25 gateway or an X.75 gateway in a
network.
GCRA
general packet radio service
A packet-linked technology that enables high-speed, 115-kbit/s, wireless
Internet, and other data communications.
general virtual circuit interface (GvcIf)
GvcIf is a networking feature providing circuit establishment between LAN/
WAN services.
generic cell rate algorithm (GCRA)
An algorithm used in a Nortel Multiservice Switch ATM network to monitor and
police network traffic. In Multiservice Switch traffic management, GCRA is
used by usage parameter control (UPC) to enforce conformance at the source
ATM terminal.
generic flow control (GFC)
A four-bit field in the ATM cell header at a user-to-network interface intended
for traffic flow control between the user and network equipment.
generic queue manager (GQM)
A traffic management device (ASIC) which resides on GQM function
processor (FP) cards. The GQM descends from other traffic management
devices such as the AQM and QRD, and is capable of OC-48. It differs
considerable from the other traffic management devices in that it will schedule
up to a single OC-48 channel, its scheduling algorithms are frame or cell
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agnostic, it can shape four emission priorities (EPs), and it does not have a
usage parameter control (UPC) function because that is done by a different
ASIC called ATLAS (on the same card).
global rerouting domain
In the context of the global rerouting protocol, the entire set of nodes in the
PNNI network including all nodes belonging to all local rerouting domains.
Global System for Mobile Communications
A standard digital cellular phone service used in Europe and Japan, to ensure
interoperability between countries.
good-put
In an ATM network, the measurable amount of traffic that is transmitted from
source to destination that can be successfully segmented and reassembled
by the end systems. A high good-put means that few or no cells were
transmitted that could not be reassembled into frames.
GPRS
group address
In ATM networking, identifies a group of endstations. The ATM group address
is characterized by the group address AFI. The ATM groups and AFIs are
defined in the ATM Forum User-to-Network Interface Signaling Specification
Version 4.0 (af-sig-0061.000), Annex 5.
GQM
GSM
GvcIf
H.248
The ITU-T gateway control protocol. H.248 is one control interface used
between the media gateway controller and the Media Gateway.
half session (HS)
A session-layer component consisting of the combination of data flow control
and transmission control components comprising one end of a session.
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hard rerouting
HDB3
HDLC
HDLC mode
HDLC-transparent data service (HTDS)
A service that transports HDLC-framed data across the network without
interpretation, except that interframe flags are not transmitted. The efficiency
of the transmission is increased by not transmitting flags.
header error control (HEC)
A CRC code found in the last byte of the ATM cell header that is used for
verifying cell integrity.
hello packet
A type of PNNI routing packet that neighboring logical nodes exchange.
Hello protocol
The Hello protocol is a neighbor discovery protocol run over private network-
to-network interface (PNNI) links between lowest level nodes and logical
group nodes (LGNs).
HEP
HG
hierarchically complete source route
A stack of DTLs that represent a route across a PNNI routing domain. A DTL
is included for each hierarchical level between and including the current level
and the lowest visible level in which the source and destination nodes are
reachable.
high-density binary 3 zero maximum encoding (HDB3)
An encoding technique used to transfer bits over E1 and E3 lines. To ensure
1’s density, HDB3 substitutes a bipolar violation where four or more 0s are to
be sent in a row.
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high-level data link control (HDLC)
An ITU-TSS link layer protocol standard for point-to-point and multipoint
communications.
high-speed serial interface (HSSI)
An EIA/TIA-613 physical layer standard. Similar to V.35 and V.11, HSSI is an
interchange circuit that transfers serial data between DTE and DCE at speeds
ranging from 1 Mbit/s to 52 Mbit/s.
hitless CP switchover
The switch of activity from the active CP to a standby CP without restarting the
FPs on the shelf. FPs that support hitless CP switchover continue,
uninterrupted, to provide service. FPs that do not support hitless CP
switchover must restart and do not provide uninterrupted service.
hitless services
1
A service is hitless when the software that provides the service can run
uninterrupted, even when the hardware providing the service changes.
With hitless services, traffic incurs minimal interruption and established
connections stay up. Nortel Multiservice Switch software applications and
features are categorized based on their ability to provide hitless services.
2
3
4
hitless software migration (HSM)
Hitless software migration allows a shelf (CPs and FPs) to migrate from one
version of software to another without interrupting the services being provided
by that shelf.
holding priority (HP)
In an ATM network, a priority scheme that is assigned to all bandwidth non-
elastic ATM connections to indicate the relative importance of each
connection. When a loss of bandwidth occurs, connections with lower holding
priority are released first.
In a PORS network, a parameter that indicates the tolerance of a connection
for path bumping. A connection with a lower holding priority can be bumped to
an alternative path or terminated by a connection with a higher priority.
hop by hop route
A routing approach in which each node along the path uses its own routing
knowledge to determine the next hop of the route. The expectation is that all
nodes choose consistent hops so that the call reaches the requested
destination.
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hop count
The number of hops it takes for a packet to make it from a source to a
destination, that is the number of nodes (routers) between a source and a
destination. Each switch or router traversed by a packed is considered a hop.
horizontal link
A link between two logical nodes that belong to the same peer group.
host computer
The central controlling computer in a network of computers. It allows lower-
level terminals to work through it to obtain access to other computers and their
stores of information.
hot equipment protection (HEP)
A carrier grade feature that provides a customer with the capability of setting
up a sparing configuration that allows for hitless switch-over capabilities.
hot standby
Hot standby applications and features offer hitless services during an FP or
CP switchover. During an equipment switchover, hot standby applications
incur minimal traffic interruption and established connections stay up.
hot swapping
Hot swapping of a data path refers to a service switchover while the node is in
service.
HP
HS
HSM
HSSI
HTDS
hunt group (HG)
Hunt groups are a group of network addresses (DNAs) reachable from a
unique DNA and configured so that an incoming call automatically searches
for an available address in the group.
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I80960
A 32-bit Intel embedded processor that is one of the processing engines of
control processors and function processors. It coordinates all activity on these
processor cards.
IAD
IBGP
ICR
ICMP
IGMP
IGP
IISP
IMA
IME
IMA link group
IMUX
import policy
A collection of rules that govern the reception of route information. These
policies are used by the BGP, EGP, and RIP route management protocols.
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in-band synchronization
The process through which the accounting system takes a simultaneous
snapshot of the accounting data at each end of the virtual circuit. This
snapshot is used to generate an accounting record.
incumbent segment
An active connection segment that is in the process of being replaced by an
alternate connection segment.
independent link
A single physical link used directly by the ATM layer. It is not part of an IMA
group.
independent transmit clock (ITC) mode
An IMA configuration in which the transmit clock on one or more physical links
in the IMA group is derived from different sources. This is contrasted with
common transmit clock (CTC) mode.
independent VCC
A VCC that is not associated with a virtual path terminator.
induced uplink
An induced uplink is an uplink that is created by a logical group node (LGN)
by aggregating uplinks advertised by its corresponding lower level peer group
leader (PGL).
ingress node
1
The first Nortel Multiservice Switch node that decides to which egress
node the data packet is sent.
2
ingress traffic
Ingress traffic refers to the traffic entering a Nortel Multiservice Switch network
through an access point.
initial cell rate (ICR)
In ATM ABR networking, the rate at which the ABR source transmits cells,
both initially and after an idle period.
inside link
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instance
Information (such as a decimal or a string) appended to the component type.
When more than one of a component type exists, they are differentiated by an
instance value.
instance type
The data type for a component instance. The null data type is used for non-
replicated components, and the compound data type is used for multi-indexed
components.
instance value
The actual component instance value as permitted by its type.
instantiating
In PORS, the process of laying down the path on the selected route. Once the
route is selected by the route selector and returned to the source endpoint, the
source endpoint starts the procedure of setting up the path.
inter-domain link
A PNNI link that connects two nodes that are in different local rerouting
domains or a link using a non-PNNI signaling interface such as UNI, IISP, and
AINI.
Integrated Alarm Display (IAD)
A Nortel Multiservice Data Manager Advisor tool used to display alarms.
integrated local management interface (ILMI)
A management interface at an ATM interface that consists of a management
information base (MIB) on each side of the UNI and an SNMP-based protocol
for exchanging information in the MIBs across the UNI.
integrated services digital network (ISDN)
A digital technology that provides combined voice and data services. BRI
access to an ISDN switch provides 2B+D (two 64 kbit/s B-channels and one
16 kbit/s D-channel) over an existing copper telephone line.
Out-of-band signaling is sent over the D-channel to request the setup of one
of the B-channels (for high-speed data or voice applications) or of the D-
channel for low-speed data (which can be multiplexed with the signaling and
other low-speed data applications from other terminals on the same loop).
interface management entity (IME)
The ATM interface over which ILMI is operating.
interface protocol
1
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2
3
4
interior gateway protocol (IGP)
An Internet protocol used to exchange routing information with an
Autonomous System.
interim interswitch signaling protocol (IISP)
IISP provides interconnection between Nortel Multiservice Switch nodes as
well as interconnection between Multiservice Switch and non-Multiservice
Switch nodes (Nortel Networks-family nodes and devices from other vendors).
internal border gateway protocol (IBGP)
BGP configuration in which sessions are established between routers in the
same autonomous systems (ASs). See also border gateway protocol (BGP)
internal gateway
A DPN logical connection that runs over a Nortel Multiservice Switch trunk
interconnecting two Multiservice Switch nodes in different RID subnets. A
Multiservice Switch trunk supporting internal gateways continues to operate
as a normal Multiservice Switch trunk in supporting non-DPN type of traffic.
internal reachable address
In PNNI networking, an address of a destination point that is directly attached
to the logical node that advertises the address.
internal router
A router with all directly connected networks belonging to the same area.
There can be internal routers in the backbone area if all of their interfaces are
in the backbone.
International Telecommunication Union - Telecommunication
Standardization Bureau (ITU-T)
A European standards body formerly called Comité Consultatif International
Télégraphique et Téléphonique (CCITT).
Internet
A network of two or more networks. Usually these networks use different
governing protocols or are administratively or physically separated.
Internet addressing
A system of addressing using a 32-bit address, usually divided into four octets.
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Internet control message protocol (ICMP)
A collection of error conditions and control messages exchanged by IP
modules in both hosts and gateways. Examples consist of echo requests and
replies and notification of discarded datagrams.
Internet group management protocol (IGMP)
A protocol that is used between routers and locally attached hosts to
communicate multicast group membership information.
Internet protocol (IP)
A protocol suite that operates within the Internet as defined by the requests
for comment (RFC). This term can also refer to the network-layer (level 3) of
this protocol stack-the layer concerned with routing datagrams from network
to network.
Internet protocol interface over frame relay (IPIFR)
Allows a Nortel Multiservice Data Manager workstation to communicate with
Nortel Multiservice Switch nodes over frame relay. Once the connection
between a workstation and a node has been established, Multiservice Data
Manager can connect to the node over frame relay and exchange IP
datagrams.
Internet protocol interface over virtual circuit (IPIVC)
In Nortel Multiservice Switch device’s initial releases, FTP, Telnet, Ssh, and
FMIP protocols are implemented over TCP/IP protocols using the IPIVC
system. This system allows Nortel Multiservice Data Manager workstations to
communicate with Multiservice Switch nodes by way of X.25 on DPN-100.
Once the connection between a workstation and a DPN-100 module has been
established, Multiservice Data Manager can connect to the node over the
X.25 virtual circuit and exchange IP datagrams. The ftp connections can be
either secure or non-secure as described in the Multiservice Data Manager
Security User Guide.
inter-region Multiservice Switch trunk
A Nortel Multiservice Switch trunk that is a link between two border nodes in
different topology regions.
interrupting mode
intra-domain link
A PNNI link that connects two nodes that are in the same local rerouting
domain.
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inverse multiplexing for ATM (IMA)
A feature available on Nortel Multiservice Switch nodes that supports the
transparent transmission of ATM cell data over a link group. IMA transparently
distributes a single stream of ATM layer cell traffic onto multiple physical links
for transmission across the links, and then combines the traffic back into the
original ATM layer cell sequence at the remote end.
inverse multiplexing for frame relay (IMUX)
A frame-based inverse multiplexing function provided by the multilink frame
relay (MLFR) service.
inverse-UPC shaping
This form of shaping uses dynamic rate changes so that the resulting cell
stream exactly conforms to the requirements of a dual leaky bucket UPC
enforcer. Also known as dual-leaky-bucket or VBR shaping.
IP
IP address owner
The VRRP router that has the virtual router’s IP address(es) as real interface
address(es).
IP class of service (COS)
Provides four different classes of service for different types of IP traffic. With
IP COS, you can define a set of policies that identify different types of IP traffic
and specify the class of service to pass the IP traffic through the network.
IP COS
IP multicast forwarding
A packet forwarding mode that delivers IP multicast packets to a group of
nodes interested in receiving those packets in an IP network.
IP multicast forwarding table (FWD)
A forwarding table that performs exact match and best match for IP multicast
traffic.
IP multicast routing database (RDB)
A routing database for IP multicast traffic.
IP multicast routing table manager (MRTM)
A routing table manager for IP multicast traffic.
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IPSec
A security feature that defines a suite of cryptographic protocols and an
architecture used to protect packets at the network layer.
IP tunneling
A feature available on Nortel Multiservice Switch nodes that allows you to
connect physically separate IP networks that share the same address space
through an IP network on a different address space.
IPIFR
IPIVC
Ipv4Label
The BGP address family used for Carrier's Carrier to distribute routes and
labels associated with them. It consists of both the address family identifier
(AFI) and the subsequent address family identifier (SAFI). Ipv4Label
represents the AFI/SAFI value of 1/4.
Ipv4MplsVpn
The BGP address family used for BGP/MPLS VPNs to distribute VRF routes
and service labels associated with them. It consists of both the address family
identifier (AFI) and the subsequent address family identifier (SAFI).
Ipv4MplsVpn represents the AFI/SAFI value of 1/128.
ISDN
ISO
International Organization for Standardization.
isochronous
A data bit stream that has equal time between bits.
ITC mode
ITU-T
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JT2
A 6312 kbit/s interface defined in TTC JT-G.703. Consists of a framing
structure of 789 bits made up of 98 time slots (8-bit) followed by 5 framing bits
as defined in TTC JT-G704.
junctor virtual circuit (JVC)
A virtual circuit used to extend the subnet to the legacy data module in a
Passport 4400 access unit. The JVC permits the establishment of a general
virtual circuit (GVC) connection over a Multiservice Passport access network
link (MPANL) service.
JVC
label switching router (LSR)
A core node that performs label switching in an MPLS network.
LACP
LAG
LAN
LAPD
LAPF
LATA
last common node
Network node where the information flow uses an established call/connection
to a party at the ingress, and an unused interface at the egress.
late packet discard (LPD)
A packet discard mechanism that works in conjunction with PPD. LPD
preserves the end-of-packet cell of a packet that is subject to PPD, which
permits identification of the beginning of the subsequent packet.
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layer
LC
In the OSI reference model, a collection of related network processing
functions that comprise one level of a hierarchy of functions.
1
2
LCN
LCo
See logical channel number.
LD-CELP
LDS
leaf
Is sometimes used interchangeably with party. However, a leaf more
accurately denotes any single destination point of a point-to-multipoint call.
LEN
level
In ATM networking, a level is the position in the PNNI hierarchy at which a
particular node or peer group exists. A level that has a smaller numerical value
implies greater topology aggregation. Conversely, a level that has a larger
numerical value implies less topology aggregation. Smaller numerical values
indicate high levels while larger numerical values indicate lower levels.
LG
LGN
LGN Horizontal Link Hello protocol
The LGN (logical group node) Horizontal Link Hello protocol is a protocol run
over an SVCC RCC channel to discover and monitor logical links between
neighboring logical group nodes.
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LIF
line
1
A dedicated private or leased facility that connects user equipment to the
Nortel Multiservice Switch network. A line can be a link.
2
3
In SONET, a part of a connection between STS-n multiplexers.
In SDH, a part of a connection between STM-n multiplexers.
line automatic protection switching (APS)
1
Automatic protection switching applied to SONET and SDH lines.
Sometimes called linear APS in some specifications, such as Telcordia
GR-253.
2
line sparing
link
1
2
A channel or path between network entities that includes the connection
and the interface devices.
A component model data type used to relate non-hierarchical
components. It is represented using an attribute on either component with
a value being the other component name. If one side of the link is
changed, the other is automatically updated.
link access procedure on frame relay (LAPF)
The data link layer protocol that has been defined for ITU-T Q.921. LAPF is an
ISDN access protocol used with links that are established on frame relay.
link access procedure on the D-channel (LAPD)
The data link layer protocol that has been defined for ITU-T Q.921. LAPD is
an ISDN access protocol used with links established on a D-channel.
link aggregation (LAG)
Logical grouping of multiple Ethernet links.
link aggregation control protocol (LACP)
This protocol is used to exchange LAG information between two nodes.
link controller (LC)
The integrated circuit (ASIC) that provides a serial data interface into the
Nortel Multiservice Switch node.
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link delay synchronization (LDS)
A circumstance in which the receiving end of an IMA link group has measured
and compensated for the differential delay over a physical link. If this is the
case, then the link is considered to be in link delay synchronization (LDS).
link group (LG)
1
A group of links (Nortel Multiservice Switch trunks or DPN gateways)
between two nodes that can share traffic between the nodes. This allows
the available bandwidth between the two nodes to be greater than that of
a single link. A maximum of four links in a link group can be supported.
2
An IMA link group refers to the combination of multiple physical links that
use the inverse multiplexing process to transmit traffic across these links.
A link group is presented as a single link to the ATM layer. A link group
originates on one FP running the IMA feature and terminates on another
FP running the IMA feature (typically these FPs are on two different
Multiservice Switch nodes). Any link group can be composed of up to eight
DS1/E1 physical links on an FP running IMA.
link-level protocol (LLP)
A protocol that permits encapsulation of multiple protocols over a single ATM
virtual circuit.
link state advertisement (LSA)
A packet of information that determines the shortest path to a destination.
link-state algorithm
A routing technology in which each node broadcasts to all other nodes its view
of the links. When every node in the network does this, all nodes can derive
the complete topology and perform operations on that topology.
link state parameter
Information that captures an aspect or property of a link.
live alarm
An alarm that is issued by a fault or other significant event, rather than in
response to a replay command.
LLP
LMI
LN
1
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2
LNID
LNN
Load Re-balancing on Parallel Links
When a new Private Network-Network Interface (PNNI) parallel link is added,
or an existing PNNI parallel link is dropped and then recovered, the bandwidth
is distributed equally across the parallel links.
load sharing
Load sharing is the process by which traffic is divided over links in a link group
on a packet by packet basis.
load spreading
If there is more than one equal path to a destination, Nortel Multiservice
Switch node’s will pick two of them. Load spreading is the process by which
nodes divide traffic, on a VC basis, over the two link groups on those paths
and the links in the link group. The algorithm used ensures (under normal
conditions) that all the traffic for a given VC follows the same path and uses
the same links along that path.
local access transport area (LATA)
Also referred to as a service area by some Bell Operating Companies (BOC),
a LATA serves two basic purposes: to provide a method for delineating the
area within which the BOCs may offer services and, to provide a basis for
determining how the assets of the former Bell System were to be divided
between the BOCs and AT&T at divestiture.
The United States has been divided into 200 LATAs by the AT&T Modified
Final Judgment. Each BOC may service more than one LATA, but BOCs are
generally constrained from providing long distance service between LATAs.
Long distance service within a LATA is provided by the LEC. Service between
LATAs is provided by an IEC.
local address resolver
A component of connection address resolution (CAR) that performs the
resolution of a destination address at the local level.
local area network (LAN)
A network that connects microcomputers, workstations, printers, and other
devices together, limited to local distances.
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local bus
A 32-bit bus on a processor module joining local memory (SRAM and DRAM),
boot ROM, SBIC, and the microprocessor.
local domain edge node
A node that has at least one inter-domain link.
local domain link type
In the context of the local rerouting protocol, a PNNI link can be described as
an intra-domain link or an inter-domain link.
local leaf
Relevant to a single node in a PMP call. A local leaf is on a branch with a local
root, across the Nortel Multiservice Switch node back plane, forming a new
link to the remote leaf.
local management interface (LMI)
In frame relay, the part of the C-plane that manages the PVCs.
local memory
A RAM that stores code and program data for the microprocessor.
local node name
The name of a Nortel Multiservice Switch node. It forms the initial part of all
component names, but is usually suppressed. For example, em/ottawa lp/0
appears as lp/0.
local rerouting domain
In the context of the local rerouting protocol, a group of nodes linked by intra-
domain links.
local root
Relevant to a single node in a PMP call. A local root is on a branch with a local
leaf across the Nortel Multiservice Switch node backplane. A local root
multicasts copies of incoming cells to each local leaf.
LODS
LOF
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logical channel (LC)
A logical division of a Nortel Multiservice Switch trunk that constitutes part of
a path. A logical channel is used in a single direction and is locally identified
by a logical channel number.
logical connection (LCo)
A logical connection is an association between two endpoints in the Nortel
Multiservice Switch network for the purpose of exchanging data.
logical group node (LGN)
An abstract representation of a lower level peer group as a single point for
purposes of operating at one level of the PNNI routing hierarchy.
logical link
The combination of logical node identifier and logical port identifier.
logical network (LN)
A logical network is a set of Nortel Multiservice Switch nodes and transport
facilities (links) that support a particular address plan and packet format.
Logical networks allow different customers to set up logically distinct networks
using the same physical resources—even the same address scheme, routing
protocol, packet formats, and packet forwarding algorithms.
logical network number (LNN)
An identifier for a logical network.
logical node (LN)
A lowest level node or a logical group node.
logical node identifier (LNID)
A string of bits that unambiguously identifies a logical node within a routing
domain.
logical port identifier (ID)
Identifies a logical port on the logical node that the connection is to traverse
or has traversed.
logical processor (LP)
A body of software that can be mapped to a processor card to deliver one or
more Nortel Multiservice Switch services or capabilities. Logical processor-to-
card mapping can vary depending on sparing configuration and hardware
availability.
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logical processor type (LPT)
Defines the characteristics of an LP. The LPT specifies which software needs
to be loaded and provides some processor engineering parameters.
long loop
The ABR VS/VD scenario where FRM cells transit the node to the egress FP
before the node turns them around to become BRM cells.
LOS
loss of delay synchronization (LODS)
When the delay on a physical link changes such that it exceeds the maximum
differential delay specified for the IMA link group, the link is considered to have
lost its delay synchronization. That is, the link has experienced a loss of delay
synchronization (LODS), and is deactivated from the link group.
loss of frame (LOF)
This failure condition is declared after severely errored frame (SEF) defects
have been detected for at least two seconds for a DS1, DS3, E1, or E3.
loss of IMA frame (LIF)
A failure condition in which IMA framing is lost on a link that is part of an IMA
link group.
loss of signal (LOS)
For DS1, DS3, E1, and E3, this event is detected at a line interface when
175+/-75 contiguous pulse positions with no pulses of either positive or
negative polarity are detected. An LOS failure condition is declared after LOS
defects have been observed for at least 2 s.
Low-delay code excited linear prediction (LD-CELP)
A 16 kbit/s compression algorithm used to encode voice data, based on
ITU-Trecommendation G.728.
low-entry networking (LEN) node
In Systems Network Architecture (SNA), a physical unit type 2.1 with a control
processor does not communicate with other nodes. LEN nodes support
logical unit protocols.
lowest level node
A leaf in the PNNI routing hierarchy. A lowest level node is an abstraction that
represents a single instance of the PNNI routing protocol. Lowest level nodes
are created in a switching system through provisioning and are not created
dynamically.
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LP
LP instance
One defined instance of a logical processor. In addition, when a spare card is
available, an LP instance can be used to implement equipment sparing.
LPD
LPT
LRB
LSA
LSR
MAC
make-before-break rerouting
main card
The primary processor card on which an LP is provisioned to run. In a sparing
configuration, a main card carries traffic unless a failure causes traffic to
switch to a spare card.
MAN
Management Data Provider (MDP)
The Management Data Provider (MDP) host stores and converts accounting
data from DPN-100 and management data (accounting, statistics, alarms,
SCNs, and logs) from Nortel Multiservice Switch nodes prior to transferring
the data to either a Billing host or a Network Engineering host. The
Management Data Provider replaces the Accounting Data Server.
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management data router (MDR)
Collects surveillance data from multiple Nortel Multiservice Switch nodes and
distributes it to multiple Nortel Multiservice Data Manager network operation
centers.
management information base (MIB)
A database containing configuration and status information relating to a
specific managed object or objects. Provides a description of all the
components and variables within a component that a network management
system can access. It provides the way of naming each of these components
and variables. MIB is a concept defined in network management standards
such as SNMP.
manual CLR alarm
A CLR alarm issued in response to manual intervention, rather than in
response to the system detecting that the associated fault condition no longer
exists.
manual path
In path-oriented routing, specifying the series of Nortel Multiservice Switch
trunks that form the path instead of letting the system create the path
automatically.
marker protocol
A protocol that is used by link aggregation to transfer a conversation from one
logical link to another without misordering cells.
maximum burst size (MBS)
One of a set of traffic characterization values used to define traffic
characteristics through the traffic descriptor types. MBS defines the length in
cells of a traffic burst relative to the peak cell rate (PCR), which it cannot
exceed, and the sustainable cell rate (SCR), which it can exceed but only for
the time period defined by BT.
maximum transmission unit (MTU)
1
The size (in bytes) of the largest datagram that a router or interface can
transmit.
2
The size of the largest frame that a link can transmit.
MBR
MBS
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MCDN
MCR
MCS
MDCR
MDP
MDR
measurement interval (T)
The time interval over which rates and burst sizes are measured. In general,
its duration is proportional to the burstiness of the traffic.
media access control (MAC)
A 48-bit address unique to each local area network interface. This address is
usually derived from the manufacturer’s ID number and the serial number of
the interface chip set.
media gateway (MG)
A device that provides media transformation from TDM to VoIP or ATM under
the control of a media gateway controller via a device control interface such
as VGCP. The MG handles all the bearer traffic functionality.
media gateway controller (MGC)
A device that acts on user- or peer-device signaling to create or delete a
narrowband connection on a media gateway via a device control interface
such as VGCP. The MGC handles all the signaling and call control
functionality.
membership scope
In PNNI networking, the level of the routing hierarchy within which
advertisement of a given address is constrained.
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Meridian 1 ISDN Primary Rate Interface (MCDN)
A common-channel signaling protocol intended for use between members of
the Nortel Networks Meridian family of Private Telecommunication Network
Exchanges. The signaling information is carried through time slot 16 of a
2.048 Mbit/s digital transmission system. Similarly, it is carried through time
slot 23 of a 1.544 Mbit/s digital transmission system.
metric
A metric is a number that is used to represent the attractiveness (a smaller
metric is more attractive) of a link or LinkGroup to a routing protocol. Some of
the metrics used by Nortel Multiservice Switch are
•
•
•
cost: a user-definable value
delay: measured by the system (a lower metric represents a lower delay)
throughput: measured by the system (higher speed links have lower
metrics)
metropolitan area network (MAN)
A network that spans a city. It is bigger than a local area network (LAN) but
smaller than a wide area network (WAN).
MG
MGC
MIB
MIB view
A specific set of components in the MIB hierarchy that is created from subsets
of included and excluded subtrees.
MID
minimum cell rate (MCR)
A measure of the minimum useful data rate for the given ATM UBR service
category. This term is used interchangeably with MDCR.
minimum desired cell rate (MDCR)
A measure of the minimum useful data rate for the given ATM UBR service
category. This term is used interchangeably with MCR.
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mixed-mode (MX)
A type of function processor that incorporates ports supporting different types
of optical fiber (Meridian devices only). A mixed-mode FP contains at least
one port that operates in single mode and one port that operates in
multimode.
MLFR
MM
MMTC
model
A way of describing Nortel Multiservice Switch nodes for management
purposes. The two supported models are the component model and the
SNMP model.
module identifier (MID)
MIDs identify individual Nortel Multiservice Switch nodes or DPN-100 access
modules.
MPANL
MPLS
MPS
MR
MSA
MSA8
MSP
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MTU
mu-law
Normally written as m-law. A technique for translating pulse code modulated
voice into 64 kbit/s digital voice channels. m-law is used in North America,
multicast border router (MBR)
A router that participates in more than one multicast domain.
multicast domain
A set of one or more contiguous links with optional routers that implement the
same multicast protocol configured to operate within a common boundary.
multicast forwarding
A packet forwarding mode that delivers the packet to all nodes in the logical
network.
multiframe
A group of frames seen as a single entity and located by a multiframe signal.
Multiframing is a concept used in E1 and DS1 protocols.
multihomed address
In ATM PNNI networking, an address that is advertised by multiple PNNI
nodes.
multi-hop BGP
Multi-hop border gateway protocol (BGP) refers to a BGP connection
established between peers that are not directly connected and can span
across multiple hops. See also external border gateway protocol (EBGP)
multilink frame relay (MLFR)
A service for FrUni and FrNni connections. MLFR provides physical interface
emulation for frame relay devices. The emulated physical interface consists of
one or more DS1 links, called bundle links, that are aggregated into a single
bundle that offers greatly expanded bandwidth. This service also provides a
frame-based inverse multiplexing function, sometimes referred to as a inverse
multiplexing for frame relay (IMUX). This definition is in accordance with the
Frame Relay Forum Implementation Agreement FRF.16.
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multimedia traffic classes (MMTC)
Subscriber options that enable you to select the traffic handling preferences
from the network to meet the application requirements. MMTC handle delay-
sensitive multimedia traffic and minimize the delay transfer time and delay
variance through the Nortel Multiservice Switch network.
multimode (MM)
Optical fiber that is capable of propagating light signals of two or more
wavelengths (modes).
multiple priority system (MPS)
Nortel Multiservice Switch system proprietary priority system which defines
traffic importance in terms of three emission priorities and four discard
priorities.
multiport aggregate device
A multiport aggregate device breaks out the ports of the 32-port E1 AAL
function processor (FP). Each multiport aggregate device provides
connections for 16 E1 ports. You must use two multiport aggregate devices to
break out all the ports of the FP.
multiprotocol label switching (MPLS)
MPLS is a label-swapping, networking technology that forwards packet traffic
over multiple, underlying layer-2 media. This technology integrates layer-2
switching and layer-3 routing by linking the layer-2 infrastructure with layer-3
routing characteristics. Layer-3 routing occurs at the edge of the network, and
layer-2 switching takes over in the MPLS network core.
multipurpose voice platform enhanced echo cancellation (MVP-E)
An MVP function processor with an on-board daughter card that provides
echo cancellation capabilities according to ITU-T G.164, G.165 and G.168.
The five types of Nortel Multiservice Switch MVP-E function processor are 1-
port DS1 MVP-E, 1-port E1 MVP-E, 4-port DS1 MVP-E, 4-port E1 MVP-E and
1-port TTC2M MVP-E.
multi-rate (MR)
The capability of a function processor (FP) to operate at multiple line rates
according to specific configurations. The 4-port multi-rate POS and ATM FP
(4pMRPosAtm) is an example of a multi-rate FP.
multiservice access function processor (MSA32 FP)
A function processor possessing 32 DS1 or E1 ports. The MSA FP is capable
of running multiple services on Nortel Multiservice Switch nodes.
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Multiservice Access Function Processor (MSA8 FP), 8-port
The 8-port DS1 or E1 function processor card which provides Multiservice
capability on the Multiservice Switch 7400.
Multiservice Passport access network link (MPANL)
A Nortel Multiservice Switch link support service designed to communicate
with Passport 4400 access units. MPANL includes proprietary protocol
elements derived from ITU-T X.36 (frame relay) and signaling protocols
(Q.922 and Q.933). These protocol elements enhance the treatment of voice
traffic over links shared with application data and enable secure signaling as
a frame relay application. MPANL includes
•
components for interfacing to Passport 4400 access units using frame
relay, FrMux, and ISDN
•
•
components for traffic shaping
components for participating in Multiservice Switch voice and various VC
services
Multiservice Passport access network link signaling protocol (MSP)
This protocol allows end devices connected to a Passport 4400 unit to
interwork with end devices of a similar type in the Nortel Multiservice Switch
network. The same protocol can also allow a Passport 4400 unit to connect to
another Passport 4400 unit in a hierarchical manner.
Multiservice Switch bus
Two synchronous 32-bit 25-MHz cell buses, operating in a load-sharing
capacity, that can communicate with up to 16 function and control processors.
Each bus operates at 800 Mbit/s for a combined speed of 1.6 Gbits/s.
Multiservice Switch cluster
A group of one or more interconnected access nodes connected to the
backbone in the same RID subnet. A cluster may consist of a single node or
multiple nodes. A single-node cluster is a single cluster border node providing
access and not connected to any other access nodes. A multi-node cluster is
a group of one or more access nodes interconnected to one or more cluster
border nodes. A cluster exchanges limited routing information and no topology
information with the backbone.
Multiservice Switch subnet
A number of Nortel Multiservice Switch nodes directly connected to one
another.
Multiservice Switch trunk
Nortel Multiservice Switch node-to-Multiservice Switch node connection
supporting core networking. Multiservice Switch trunks support the dynamic
packet routing system (DPRS) and path-oriented routing system (PORS).
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Multiservice Switch trunk over ATM
The transport mechanism used by Nortel Multiservice Switch trunks to carry
cell traffic on an ATM-based interface.
Multiservice Switch trunking system
The software system that implements Nortel Multiservice Switch trunking
functions, such as managing links with other Multiservice Switch nodes or
DPN-100 modules.
MVP-E
MX
nailed-up endpoint (NEP)
An endpoint in a permanent connection. Nailed-up endpoints link the ATM
connection to Nortel Multiservice Switch trunking over ATM.
nailed-up relay point (NRP)
An intermediate or relay point in a permanent connection. Nailed-up relay
NAMS ID
of a NAMS identifier. See NN10600-060 Nortel Multiservice Switch 7400/
NAMS identifier (NAMS ID)
1
In Nortel Multiservice Switch systems, an attribute allowing the definition
of a NAMS identifier. See NN10600-060 Nortel Multiservice Switch 7400/
15000/20000 Component Reference for NAMS ID attribute description.
2
In DPN, the identifier for a subsection of a functional grouping of
administrative subsystems. See NAMS in 241-0001-002 DPN-100 List of
Terms.
native address
An address or address prefix that matches one of the summary addresses for
a given node.
NCS
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NEBS
NEP
Network Clock Synchronization (NCS) System
A system used to synchronize the clocking of multiple ports and nodes in the
Nortel Multiservice Switch network. NCS can be synchronized to the signal
originating from a single internal source or to a source external to the network.
NCS ensures the accurate transmission and reproduction of synchronous
data (for example, BTDS uses NCS).
Network Engineering host
The Network Engineering host receives Nortel Multiservice Switch system
statistics data in bulk data format from the Management Data Provider. The
data is used by this host for planning and analysis of network operations.
Network Equipment Building System (NEBS)
The Telcordia standards for power cabling, grounding, and environmental
safety, power, and operation interfaces for telecommunications equipment.
The NEBS frame is used to house telecommunications equipment.
Network Equipment Building System (NEBS) 2000 frame
A Nortel Networks universal frame used to house a Nortel Multiservice Switch
device. The installation consists of two half NEBS frames bolted together back
to back. The NEBS frame measures 600 mm in width by 600 mm in depth by
2125 mm in height.
Network File System (NFS)
A seamless file system that can operate over a whole network. It is based on
Sun’s NFS protocol and operates on IP networks using IP and UDP or TCP.
networking
Networking allows for the transfer of packets from source to destination
through Nortel Multiservice Switch routing, trunking, and traffic management
systems.
network interface specification A211-1 (NIS A211-1)
A North American variant of an ISDN CCS signaling protocol supported by
Nortel Multiservice Switch voice networking service. See also common
channel signaling.
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network interworking function (NIWF)
The FR-ATM network interworking function (NIWF) enables frame relay CPE
connectivity across frame relay networks interconnected over a backbone
ATM network. The NIWF encapsulates frame relay traffic over ATM and
multiplexes many frame relay DLCIs to one ATM VCC. The FR-ATM network
interworking function is based on the FRF.5 standard.
network management interface (NMIF)
An interface between Nortel Multiservice Switch nodes and external entities
for management purposes, using a specific protocol. The supported interface
and protocol types are: local, Telnet, Ssh, FMIP, and FTP (both non-secure
and secure).
network management interface system (NMIS)
Manages interfaces between the Nortel Multiservice Switch software and
external network management systems. Through NMIS, commands can be
issued to Nortel Multiservice Switch nodes from network managers, and
results returned. This allows Multiservice Switch nodes to be controlled and
monitored.
network mask
A 32-bit value that masks (or causes a router to ignore) portions of a packet’s
address. This technique allows the administrator to subdivide the logical
network from the IP address.
network processing unit
A programmable device that specializes in the processing of data packets.
network protocol
A protocol that consists of an address plan, a frame format, and a state
machine for the protocol's behavior.
network service access point address
An address used in ATM-based services (for example, PORS and Circuit
Emulation) to identify objects in a network. It is defined in RFC 1629 and in
ATM USER-Network Interface (UNI) Signalling Specification (Version 4.0),
released by the ATM Forum Technical Committee, July 1996.
network time protocol (NTP)
A public network time synchronization protocol that Nortel Multiservice Switch
XNTP software can use to synchronize the time between different nodes in a
network. RFC 1305, Network Time Protocol (Version 3), defines the standards
for this protocol.
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Network Time Synchronization (NTS) System
A system that maintains time-of-day synchronization for all devices in the
Nortel Multiservice Switch network. NTS resides in the control processor
software and synchronizes the local real-time clock interface module from an
IP-reachable network management system time server connection. NTS also
accepts local operator commands for setting the local time.
When NTS for Nortel Multiservice Switch, NTS for Nortel Multiservice Data
Manager, and NTS for DPN-100 are used together, they provide one network
time-of-day reference used by all
DPN-100 modules, Multiservice Data Manager workstations, and Multiservice
Switch nodes in the network.
network-to-network interface (NNI)
Frame relay service can be provided through a standard interface between
two frame relay networks of different manufacture. The interface is called the
network-to-network interface. For more information, see NN10600-900 Nortel
Multiservice Switch 7400/15000/20000 Frame Relay Technology
Fundamentals.
NFAS
NFS
NIWF
NMIF
NMIS
NNI
NNID
NPU
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nodal state parameter
Information that captures an aspect or property of a node.
node ID
A unique number used to identify a specific Nortel Multiservice Switch node
within a network. See NN10600-060 Nortel Multiservice Switch 7400/15000/
20000 Component Reference for more information.
Node Management System
A system that supports maintenance, monitoring, and testing of Nortel
Multiservice Switch hardware and software, as well as the facilities for
connecting Multiservice Switch devices to other network elements.
node name
A unique name used to identify a Nortel Multiservice Switch node within a
network. The name is an ASCII string that contains a maximum of 12
characters. See NN10600-060 Nortel Multiservice Switch 7400/15000/20000
Component Reference for more information.
node NSAP address
The attributes nodePrefix and alternatePorsPrefix, provisioned under the Mod
component, that are broadcast and stored in the Base Routing Topology
Database. They are also referred to as node addresses. See NN10600-435
Nortel Multiservice Switch 7400/15000/20000 Operations: Path-Oriented
Routing System for more information.
non-adjacent network identifier (NNID)
A numeric identifier assigned to a network that is indirectly connected to this
network through one or more adjacent networks.
non-associated signaling
Uses separate logical paths and multiple nodes as signaling links.
non-branching node
A node that cannot currently support additional branching points for point-to-
multipoint calls.
non-elastic connection
An ATM connection type that cannot respond to changes in bandwidth over an
ATM link by decreasing or increasing its data rate. If there is insufficient
bandwidth, the connection is released. Compare with elastic connection
non-facility associated signaling (NFAS)
A type of signaling used by PBXs whereby a single D-channel spans multiple
DS1 or E1 links.
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non-real time variable bit rate (NRT-VBR)
A QOS class that defines the throughput connection history as bursty with an
expected low cell loss ratio (CLR) for transmitted cells. NRT-VBR supports
statistical multiplexing for connections, with no associated delay bounds. NRT-
VBR is designed to support non-real time applications.
non-operational card
A processor card that cannot provide service. The card can be absent,
unprovisioned, locked, or has not yet finished loading its software.
non-switched voice
1
A Nortel Multiservice Switch 7400 node feature in which narrowband
traffic between TDM nodes is transported transparently over an ATM
network.
2
Nortel Multiservice Data Manager
In general, a system that helps to control, provision, and monitor the Nortel
Multiservice Switch network. In Nortel Networks documents, this term most
often refers to Multiservice Data Manager, Nortel Networks’s proprietary
network management system.
Nortel Multiservice Data Manager software
A network management software system for controlling, provisioning, and
monitoring DPN and Nortel Multiservice Switch networks. It consists of a set
of applications supported by a common user interface running on a UNIX
operating system. Multiservice Data Manager uses a commercially available
hardware platform, such as a Sun SPARC station.
NPI
NRP
nrtVBR
NSAP address
NscNull
A Network Systems Corporation (NSC) proprietary encapsulation method that
supports IP traffic over permanent virtual circuits (PVC).
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NTP
NTS
numbering-plan indicator (NPI)
The part of a given data network address that defines the numbering plan to
which it belongs. Examples of numbering plans defined by ITU-T are X.121
and E.164.
OAM
OC-3
Optical carrier level 3. In SONET networks, OC-3 is the optical form of the first
SONET multiplexing level when it is transmitted through an optical fiber. The
155.52 Mbit/s OC-3 signal is made up of three multiplexed OC-1 basic
channels.
OC-12
An optical carrier signal in the SONET optical format that is 12 times the OC-
1 rate.
OC-48
A high-speed optical carrier signal in the SONET optical format providing a
line rate of 2.488 Gbits/s, ATM services, and traffic management.
OC-N
Optical Carrier level N. The optical signal that results from an optical
conversion of an STS-N signal.
off-network call
A call destined to another network. An off-network call crosses one or more
gateways.
on-network call
A call that is routed internally through the SCR and DCR systems to a
destination within the network.
open shortest path first (OSPF)
An IP routing model defined in RFC 1583, whereby the shortest route to a
destination is calculated from a database of link states.
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Open Systems Interconnection (OSI)
A suite of communication protocols, network architectures, and network
management standards produced by the International Standards
Organization (ISO). The aim of OSI is to provide information transfer in a
nonproprietary environment. The protocols are open in nature, that is, defined
in an agreed forum by vendors and government committees.
operations, administration, and maintenance (OAM)
A segment boundary associated with an ATM interface or a specific
connection passing through that interface.
If the interface is on an OAM segment boundary, all connections passing
through the interface terminate OAM segment loopback cells. If the interface
is not on a segment boundary, OAM segment loopback cells pass through
transparently. The setting for the segment boundary at the interface level can
be overridden at the connection level for nailed-up relay points in an ATM
bearer service connection.
operational attribute
Provides information or data used for monitoring the operation of Nortel
Multiservice Switch nodes and services. The values of operational attributes
are not retained across system restarts. These values cannot be provisioned,
but some of them can be set. Operational attributes include information such
as component OSI management state and statistical data.
operational card
A processor card that is capable of providing service. The card can operate
as either an active instance or a standby instance.
operational component
A component that is created automatically by Nortel Multiservice Switch
systems to represent some modeled entity that is dynamic in nature. An
operational component can contain only operational attributes and
subcomponents. It can also be created using operator commands.
Operational information is not retained in the event of a power outage.
optimization
A PORS feature that allows operational paths to be evaluated based on their
current path characteristics against new paths that are determined by Route
Selector. If the new path can minimize the original paths provisioned metric
(cost or delay), then the current path will be moved to the more optimal path.
optimization metric
An optimization metric refers to the route computation criteria that is
minimized when finding the best path for a call.
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option
An option modifies the behavior or provides more information about a verb
being applied to a component. For example, the display -p option shows
provisioned data and the display -o option shows operational data.
option type
The data type of an option.
option value
The entered value for an option, as permitted by its type.
OSI
OSI state
Nortel Multiservice Switch systems define component states according to the
OSI standards. A component has three high-level state variables: operational,
usage, and administrative. These states are the primary factors affecting the
management state of the component. For more information, see
NN10600-520 Nortel Multiservice Switch 7400/15000/20000 Fault and
Performance Management: Troubleshooting.
OSI status
In addition to the three state attributes, six status attributes exist within OSI.
The primary function of these attributes is to provide additional information
about a component’s operability and usage. The attributes are: alarm status,
procedural status, availability status, control status, standby status, and
unknown status. For more information, see NN10600-520 Nortel Multiservice
Switch 7400/15000/20000 Fault and Performance Management:
Troubleshooting.
OSPF
outside link
A link to a lowest-level outside node. In contrast to an inside link (that is, a
horizontal link) or an uplink, an outside link does not form part of the PNNI
topology. As a result, nodes do not include outside links in route selection.
overflow routing
Overflow routing is the process by which Nortel Multiservice Switch networks
switch traffic from a chosen link to an alternate link, when the chosen link
becomes congested. Normal reliability traffic will overflow only to links in the
same link group. High reliability traffic can also overflow onto links in a different
link group, under certain conditions.
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P
P-node
P’
Provider node within the Carrier’s Carrier domain.
PA
PABX
packet
Packet is a term that can be used interchangeably with frame to mean a
variable-length data unit.
The term frame means a generic variable-length data unit. Packets are
generally used in layer 3 and frames in layer 2.
packet delay variation (PDV)
The measurable variation in the interval between AAL2 packets arriving at a
network element. The accumulation of this variation results in packet
clumping.
packet delay variation tolerance (PDVT)
PDVT defines the tolerance to AAL2 packet clumping that results from the
accumulating amount of packet delay variation or “jitter” in the network or
customer premises equipment (CPE).
packet forwarding
A term used to describe the process of moving packets from node to node on
packet forwarding table
Information relating to network topology that is used to route packets to paths
that are appropriate to their requirements. For example, packet headers
specify the destination and the priority of the packet. This is checked against
the packet forwarding tables, which contain information about the network.
The packet is then sent along the path that best fits its requirements.
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Packet over SONET
When POS is supported, the generic queue manager (GQM) function
processor (FP) cards of a Nortel Multiservice Switch 7400, Multiservice
Switch 15000, or Multiservice Switch 20000 nodes transmit or receive
packets over SONET (POS), or over SDH. POS handles whatever the packet-
based data is because it is a layer 3 protocol over a layer 1 transmission with
no layer 2.
packet voice gateway (PVG)
A gateway between an ATM network and service provider networks that
allows voice and voice band data traffic to be delivered over an ATM
broadband network instead of the narrowband nodes of the PSTN.
The term “PVG” is synonymous with the term “media gateway”. Refer to media
gateway (MG) (page 80) for more information.
panic
An abnormal halt to operations caused by an internal error. When an internal
error occurs and the router is unable to recover gracefully, the router
generates a text string, saves logout areas, and halts operations. A panic can
lead to a restart if the nucleus is configured to restart on error.
parent node
The logical group node that represents the containing peer group of a specific
node at the next higher level of the hierarchy.
parent peer group
The parent peer group of a peer group contains the logical group node that
represents that peer group.
partial packet discard (PPD)
A Nortel Multiservice Switch ATM traffic management strategy through which
cells are discarded if they belong to a frame that has had one or more cells
previously discarded. This strategy ensures that cells that will eventually be
discarded at the endpoints are not transmitted across the network, thereby
increasing network good-put.
party
Is sometimes used interchangeably with leaf. However, a party should more
accurately be considered as a component of a PMP call with its primary
attribute being the destination that it defines. For example, in a PMP SPVC
context, a provisioned party on the SPVC will result in a leaf when that portion
of the PMP connection terminates. Branches for the PMP call in transit nodes
can be servicing single or multiple parties, each of which will terminate at a
leaf.
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Passport 4400
A low-cost Nortel Multiservice Switch network access unit capable of
multiplexing voice, fax, video, and LAN traffic onto a frame relay interface.
Passport Carrier Release (PCR)
The Passport Carrier Release (PCR) is the software load that runs on these
members of the Nortel Multiservice Switch family:
•
•
•
•
Multiservice Switch 7400 series
Multiservice Switch 15000
Multiservice Switch 15000 VSS
Multiservice Switch 20000
One load supports all of these nodes. Each PCR is given an incremental
version number, 4.1 for example. The software version directly supports
specific hardware and software functionality and services that are added or
changed for a release.
Passport queue controller (PQC)
A hardware chip on some Nortel Multiservice Switch ATM function processors
that performs base layer functions, such as ATM cell forwarding and frame
forwarding for frame relay and IP traffic.
Passport to Passport interface (PPI)
A proprietary ATM interface between Nortel Multiservice Switch nodes. The
PPI is the Multiservice Switch system’s interim NNI (network-to-network
interface) product while NNI standards develop.
patch
A patch is a temporary enhancement or correction to the functionality of an
application version. Patches allow for a number of small changes to be made
to an application until the next version of the application is available. In
general, a new application version will incorporate all the changes in
functionality made in the preceding patches.
path
The instance of a route for a logical connection in the network that has a flow
in each direction. It is the sequence of Nortel Multiservice Switch trunks that
is used to form the connection.
path administrator (PA)
A subcomponent of Nortel Multiservice Switch Trunk component, that is used
to describe bandwidth-sharing characteristics and path activities.
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path bumping
Path bumping is the forced rerouting of an existing path by a new higher
priority path of another logical connection. Bumping happens when there is
not enough bandwidth in the selected Nortel Multiservice Switch trunk to
establish a new path. The rerouting can in turn cause bumping of other paths.
A bumped path can be rerouted on another Multiservice Switch trunk if the
route selection criteria of the path are satisfied.
path endpoint
Defines each end of a path through a Nortel Multiservice Switch network.
path optimization
A process of finding and moving active connections to more optimal routes to
provide better utilization of network resources and traffic resources. In path
optimization, the incumbent connection segment is released after the
establishment of an alternate connection segment. Path optimization is also
known as soft rerouting and make-before-break rerouting.
path-oriented routing system (PORS)
Nortel Multiservice Switch routing system in which the path is determined
when the connection is set up and is fixed for the duration of the connection.
In the event of Multiservice Switch trunk failure, the path can be rerouted. The
path then remains fixed in its new configuration. An advantage of path-
oriented techniques is that the delay variance between two endpoints can be
minimized by specifying the path in advance. This characteristic is important
for some traffic types, for example, a video signal carried over a transparent
data service (TDS).
path scope
The highest level reached in the private network-to-network interface (PNNI)
hierarchy when calculating the path.
path trace
A control plane mechanism that determines the physical nodes and physical
links traversed by new connections in the process of being established.
payload
A term used when discussing layered protocols for data communications. The
payload for one layer is the information delivered to it by the layer above it. The
header information added by that higher layer is considered to be part of the
payload.
payload type identifier (PTI)
A field in the ATM cell header that identifies the type of data carried by the cell.
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P-SPVC
P-switched permanent virtual circuit (P-SPVC)
PBX
PCM
PCR
PCS
PDU
PDV
PDVT
PDH
Plesiochronous Digital Hierarchy. An electrical transmission format. The
precursor to SDH.
PDR
PE
PE’
PEC
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peak cell rate (PCR)
The maximum transfer rate into a network, defined as upper bound on the
inverse of the time interval between two consecutive ATM cell emissions.
peer database exchange protocol
A protocol between two neighboring ATM nodes to synchronize their topology
databases over an RCC channel.
peer group
A set of logical nodes that the network engineer groups together for the
purposes of creating a routing hierarchy. All members of the group exchange
PTSEs.
peer group identifier
A string of bits that unambiguously identifies a peer group.
peer group leader (PGL)
A node in a peer group that performs the extra work of collecting, aggregating,
and building data that represents the entire peer group as a single node. The
PGL makes this representation available to the network through the parent
node.
peer group leader election (PGLE)
The peer group leader election is the process by which a single node in a peer
group is elected to be the peer group leader.
performance measurements
Real-time statistics that are collected by the data collection system (DCS)
from various applications. These real-time statistics are used for day-to-day
troubleshooting activities.
permanent logical connection (PLC)
A connection that is an association between two points in the network for the
purpose of exchanging data. The connection is called permanent because it
is set up by PORS when the service is provisioned.
permanent switched permanent virtual circuit (P-SPVC)
1
In frame relay networking, a configured connection between two SPVC
endpoints in different frame relay networks. The P-SPVC uses a switched
connection (S-SPVC) across frame relay network-to-network interfaces
(NNIs) to establish end-to-end connectivity.
2
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permanent virtual channel (PVC)
permanent virtual circuit (PVC)
1
In a frame relay network, a type of virtual circuit (VC) whose endpoints
must be configured by the network operator. It is a logical connection that,
once established, remains in place even when it is not being used. In ATM
networking, PVC is known as a permanent virtual channel.
2
permanent virtual path (PVP)
1
A PVP is a type of virtual path (VP), the endpoints of which must be
configured by the network operator. It is a logical connection that, once
established, remains in place even when it is not being used.
2
per-hop-behavior
Used in IP differentiated services to set the relative scheduling and discard
behaviors for IP packets.
per-VC queuing
A method used on ATM FPs whereby traffic from each VCC or VPC is
enqueued onto an individual queue (the VCC or VPC per-VC queue).
PG
PGID
PGL
PGLE
PGQ
PHB
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physical link
Single physical interface that interconnects two devices in a network.
PID
PIM
ping
The ping command is a debugging method used to determine the reachability
of another node, the path(s) to another node, and the round trip delay to
another node. The command is used
1
in a network supporting the RID/MID address plan for RID/MID
2
by Internet control message protocol (ICMP) to test connections to other
IP nodes
PLC
Private Integrated Services Network Exchange.
PINX
PLCP
Physical layer convergence procedure is a technique for mapping ATM cells
into DS3 or E3 frames over PDH networks.
PM
PNNI
PNNI node ID
A 22 octet string that is used to uniquely identify a node at a particular PNNI
hierarchy level.
PNNI port ID
A 32 bit integer that is used to uniquely identify a PNNI interface.
PNNI routing control channel
VCC that nodes use to exchange PNNI routing protocol messages.
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PNNI routing domain
A group of topologically contiguous systems that are running one instance of
PNNI routing.
PNNI topology state element
A collection of PNNI information that is flooded among all logical nodes within
a peer group.
PNNI topology state packet
A type of PNNI routing packet that is used for flooding PTSEs among logical
nodes within a peer group.
PMS
pools
PORS
POS
POSIX
An industry standard for Portable Operating Systems used in computer
environments.
port
1
In data communication, the part of a data processor that is dedicated to a
single data channel for the purpose of receiving data from, or transmitting
data to, one or more external remote devices.
2
3
A functional unit of a node through which data can enter or leave a data
network.
An access point (for example, a logical unit) for data entry or exit.
port ID
Identifies the egress port used by a connection. The value of the zero is
considered a wildcard.
port-VLAN
The port-VLAN is a VLAN that defines the treatment for untagged, priority-
tagged, and port-VLAN tagged traffic on a VLAN-aware Ethernet interface.
The port-VLAN tagged traffic is identified by the PVID.
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port-VLAN identifier (PVID)
The port-VLAN identifier (PVID) represents the default VLAN identifier in
VLAN mode that treats untagged, priority tagged, and PVID tagged traffic.
The PVID on Nortel Multiservice Switch nodes is always set to a value of 1.
port management system (PMS)
A software system that controls and monitors the physical interfaces that are
supported on function processors.
power converter
Converts primary power inputs into secondary operating voltages. Power
converters are available in ac and dc versions, which are not interchangeable
between ac and dc Nortel Multiservice Switch device configurations.
Synonymous with power supply.
power converter section
The part of the shelf assembly, located directly below the processor card
section, that contains the power distribution facilities for both primary and
secondary power.
power input panel
An area at the rear of the power section used to connect the power source.
PPD
PPI
PQC
PRI
primary IP address
An IP address selected from the set of real interface addresses. One possible
selection algorithm is to always select the first address.
primary path
The preferred specified path for a given specified path connection.
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primary rate interface (PRI)
An integrated services digital network (ISDN) interface standard that is
designated in North America as having a 23B+D channels. All circuit-switched
B channels and D channels operate at 64 kb/s.
priority field
A 32-bit (p-bit) field in the TCI sub-header of the IEEE 802.1Q tag header. This
field represents the user priority of an Ethernet packet.
priority guaranteed queuing (PGQ)
A queuing mechanism that ensures that cells belonging to different priority
classes sharing a link receive proper attention. The scheme enforces an
absolute priority discipline unless the service to certain lower classes is
excessively denied (that is, starved). PGQ raises the respective priority of
lower class services until they are accorded at least minimal attention.
priority-tagged
A tagged frame whose IEE 802.1Q tag carrier priority information, but carries
no VLAN identification information.
private branch exchange (PBX)
Telephone switching equipment used by a company or organization to provide
in-house telephone switching and access to the public telephone network.
private network-to-network interface (PNNI)
An ATM routing and signaling protocol that permits dynamic routing and
networking. Nortel Multiservice Switch networks support PNNI 1.0.
process identifier (PID)
PIDs identify a specific process associated with a specific data network
address.
processor
The term processor is used in Nortel Multiservice Switch documentation to
refer to a I80960 or PowerPC chip. A processor is a 32-bit embedded
microprocessor that coordinates the activities on a processor card.
processor card
A printed circuit board that provides the computation resources on Nortel
Multiservice Switch devices. These cards usually support and manage
external connections to communications facilities or networks. A processor
card slides in as one unit into one of the slots of the shelf. There are two types
of processor cards: the function processor (FP) card and the control
processor (CP) card. A processor card is often referred to as a card when it is
acting as the hardware platform of a logical processor.
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processor card section
The section of the shelf assembly that contains processor cards and the
backplane that allows the processor cards to communicate with each other.
processor control system (PCS)
Nortel Multiservice Switch subsystem responsible for managing the processor
cards. PCS detects when a processor becomes available for service, maps
the appropriate LP to execute on it, loads its software, and monitors its
execution to detect any outage that occurs. If an outage occurs, PCS invokes
the appropriate recovery procedures (such as restarting the software or
switching over to a spare processor card).
processor module (PM)
The part of some processor cards that handles the processing requirements
for a control processor (CP) and a function processor (FP).
product engineering code (PEC)
The product engineering code (PEC) of Nortel Networks hardware identifies
the part number of equipment or a set of components that combine to make
an assembly or a unit. The PEC is used by hardware installers to verify the
correct installation, replacement, or upgrade of equipment.
propagation delay
Is the time it takes one bit of information to travel along a transmission medium
from one device (Nortel Multiservice Switch node) to its neighbor device
(Multiservice Switch node). Propagation delay is a function of the speed of an
electrical (optical) signal and the distance to be travelled.
protected default route (PDR)
A protected default route is a static route to the default route 0.0.0.0,
provisioned as ‘protected’, and provisioned with multiple nextHops, each
using a unique local IP interface. Because a PDR is protected, the operational
states of these nextHops/interfaces are monitored, and the forwarding
information for this route is optimally managed to enable route reprogramming
within 1 second in the case of an active nextHop/interface failure. A protected
default route is only supported for a non-ECMP default static route.
protected static route
A protected route is a non-ECMP IP route with a set of nextHops (each using
unique local IP interfaces) which can be used to forward the packet. The
operational state of these nextHops/interfaces are monitored, and the
forwarding information is optimally managed to enable route reprogramming
within 1 second in the case of an active nextHop/interface failure.
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protocol data unit (PDU)
A unit or a packet of information exchanged between peer entities in a
particular protocol stack. The PDU is typically submitted to the next lower
(server) layer for transfer to its peer and can contain an embedded PDU of the
next higher (client) layer.
protocol independent multicast-sparse mode (PIM-SM)
A protocol for routing multicast traffic to sparsely populated receivers that
supports scalable multicast routing, independent of any unicast routing
protocol.
provider nodes (P)
The P node is a backbone router that provides the MPLS and IGP connectivity
between ingress and egress PE nodes. The P nodes never connect to CE
devices and do not keep any VPN routing information. On the MPLS
backbone, the P node acts as a core Label Switch Router (LSR), switching
MPLS packets along the Transport LSP tunnels used to forward VPN traffic
from PE to PE. This way, the P node only acts on the outer transport label
present on the packet label stack.
provider edge router (PE)
A router that is part of a service provider’s network connected to a customer
edge (CE) router. All MPLS VPN processing occurs in the PE router.
provisionable attribute
A component attribute that causes a Nortel Multiservice Switch subsystem or
service to perform or behave in a certain manner. All components that are
provisioned are saved to be used again when the system restarts.
Provisionable attribute values can be configured by the network operator or
administrator. Some components with provisionable attributes are mandatory
and are created automatically. Components with provisionable attributes can
also have operational attributes.
provisioned component
A component that is configured using operator commands. It usually contains
provisioned attributes and subcomponents. The provisioned information is
usually permanent, that is, retained in the event of a power outage.
provisioning
The act of setting the values of the data required to operate the system.
Provisioning involves adding, deleting, or changing components and setting
the values of their attributes.
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provisioning data
The data that is entered to configure Nortel Multiservice Switch modules. In
other systems, it has been known as service data, configuration data, or
tables.
provisioning journaling
Represents the journaling of configuration changes on the disk. The journal
log files that result from provisioning journaling represent the configuration
changes between the current and committed views and can be used by Nortel
Multiservice Data Manager to backup the current view off-switch.
proxy alarm
An alarm that the Nortel Multiservice Data Manager generates on behalf of a
device (for example, a Nortel Multiservice Switch node) to report an event or
condition that, while detected by the Multiservice Data Manager, could either
not be indicated by the device itself (for example, a loss of module access), or
was reported through another non-alarm means (for example, OSI State
Change, SNMP polling, or a trap). Since the proxy alarm is generated by a
Multiservice Data Manager machine, two Multiservice Data Managers
managing the same devices may generate similar but not identical proxy
alarms for the same situation (that is, the notificationId value and time-stamps,
if not available in the triggering notification, may not match between the two
proxies). A redundantly configured Multiservice Data Manager is built to
correctly handle this situation.
proxy ARP
A system by which a router responds to an ARP request in place of the actual
destination.
PTSE
PSTN
PTSP
public switched telephone network (PSTN)
The worldwide voice telephone network accessible to all those with telephone
and access privileges. The PSTN is composed of all transmission and
switching facilities and signal processors supplied and operated by all
telecommunications common carriers for use by the public. Every station on
the PSTN is capable of being accessed from every other station on the PSTN
via the use of NANP E.164 numbers. PSTN is an abbreviation defined by the
ITU-T.
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pulse code modulation (PCM)
A standardized method of producing digital speech. Defined in ITU-T G.711.
PVC
1
2
PVG
PVID
PVP
Q interface signaling (QSIG)
An internationally defined inter-PBX signaling standard. Defined in European
Telecommunications Standards Institute (ETSI) specifications.
QC
QOS, QoS, Qos
QSIG
Q-tag
An abbreviated name for the IEEE 802.1Q VLAN tag header that consists of
the TPID and TCI sub-headers. This header identifies the user priority and
LAN identification for an Ethernet packet.
QRD
quality of service (QOS, QoS, Qos)
A series of service classes that reflect the traffic importance and urgency over
a connection.
For ATM networks and services, QOS classes are defined by the ATM Forum
for UNI 3.0/3.1 and UNI 4.0. Nortel Multiservice Switch system also defines a
set of corresponding ATM QOS classes (UBR, CBR, VBR, CO, CNLS).
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queue
A linked list of buffers that stores user or control data that is incoming or
outgoing from a processor card. The data can be in the form of frames or cells.
queue length
The number of blocks that currently make up the queue.
queue limit
The maximum number of blocks that can be attained by the queue length.
queue threshold
A specific number of blocks used in the determination of the congestion state
of the queue. A queue can define several thresholds. As the queue length
crosses each threshold, the queue enters a more severe congestion state. On
ATM FPs, each queue has three thresholds in addition to the queue limit.
SBIC FPs have up to four thresholds defined.
queue controller (QC)
The part of the shared bus interface controller that maintains the linked list
pointers, blocks, buffers, and queues of the shared memory. The queue
controller manages up to 256 queues.
queue relay device (QRD)
A cell-only hardware chip on certain Nortel Multiservice Switch ATM IP
function processors that provides traffic management functions such as per-
VC queuing and congestion control.
RAI
RAIG
random early detection (RED)
A discard mechanism that inhibits the packet synchronization tendencies of IP
traffic.
RCOS
RCC
RCL
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reachability spanning tree
A collection of PNNI nodes that are reachable from the local PNNI node.
reachable NSAP address
The subcomponents address (provisioned under the Trk component) and
summaryAddress (provisioned under the Rtg component) that are broadcast
and stored in the Base Routing Topology Database. They are also referred to
as reachable addresses. See NN10600-435 Nortel Multiservice Switch 7400/
15000/20000 Operations: Path-Oriented Routing System for more
information.
real-time clock (RTC)
The clock that maintains the current time of day.
real-time statistics
Performance measurements that are collected by the data collection system
(DCS) from various applications. These real-time statistics are used for day-
to-day troubleshooting activities.
real-time statistics collection interval
The 5-minute collection interval during which real-time statistics (performance
measurements) are collected. This interval is based on network time and
occurs across the network beginning on the hour.
real time variable bit rate (rt-VBR)
A QOS class that defines a connection’s throughput as tightly constrained for
delay and delay variation. Sources are expected to transmit at a rate that
varies over time. This QOS supports statistical multiplexing or real-time
sources. It is intended to support real-time applications such as voice and
video.
RED
reduced cell loss mechanism (RCL)
The reduced cell loss mechanism is a proprietary Nortel Multiservice Switch
feature that acts to reduce cell loss while hot swapping the data path during
path optimization.
region ID
The attribute that identifies the topology region to which a Nortel Multiservice
Switch node belongs. See NN10600-060 Nortel Multiservice Switch 7400/
15000/20000 Component Reference for more information.
reload
The action of loading software from disk.
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remote alarm indication (RAI)
On DS1, DS3, E1, and E3 interfaces, a signal transmitted in the outgoing
direction when the interface determines that specific defects have persisted
long enough to declare a received signal failure.
remote defect indication (RDI)
A signal transmitted in the upstream direction when a downstream fault is
detected. The RDI signal is used at the physical and the ATM layer.
remote group
The remoteGroup component allows the X.25 DTE LLP (for example) to be
shared among a number of protocol ports. This allows separate virtual routers
to share the same physical X.25 connection into a WAN. Note that at least one
remoteGroup component is required for each X25Dte component.
remote group address
The unique address that identifies the remote group.
Remote Server Agent
An entry point for applications requiring access to Nortel Multiservice Switch
network servers.
rendezvous node
The node terminating the reroute request for an alternate connection
segment.
Remote Server Interface
A Passport 4400-based process that communicates with the RSA to access
the Nortel Multiservice Switch network servers.
rendezvous point (RP)
A router configured as a meeting point for multicast senders and receivers.
The RP acts as the root for a shared multicast distribution tree.
replicated attribute
An attribute with the replicated data type.
replicated component
A component that can have more than one instance value of a given type, for
example lp/3. Non-replicated components have the null data type, for
example, shelf.
replay alarm
A characteristic of an alarm indicating that it has previously been issued as a
live alarm, and is now being reissued in response to a replay command.
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requested shaping rate (RSR)
One of a set of ATM traffic characterization values used to define traffic
characteristics through the traffic descriptor types.
RSR defines the traffic shaping rate that is requested for a connection. This
parameter is optional. If defined, the requested rate is used as a basis for
determining the actual shaping rate; if not defined, traffic shaping is
determined by the PCR and SCR rates defined for the connection through the
traffic descriptor type.
RSR is Nortel Multiservice Switch system-specific and is not part of the ATM
Forum specification.
The five values used in the traffic descriptor parameters are peak cell rate
(PCR), sustainable cell rate (SCR), maximum burst size (MBS), cell delay
variation tolerance (CDVT), and requested shaping rate (RSR).
rerouting
Re-establishing a logical connection using different Nortel Multiservice Switch
trunks or ATM links than the last connection.
rerouting node
The node that is responsible for establishing an alternate connection segment
(rerouting segment) to a predetermined rendezvous node.
rerouting segment
A connection segment that is used to replace an incumbent connection
segment.
reset
An action taken on an entity (either a shelf or a processor card) that causes
all software on that entity to first reload and then restart. A reset can be
initiated either by an operator or by the system.
resource availability information group
The resource availability information group contains information that the PNNI
network nodes use to assign values of topology state parameters against
nodes, links, and reachable addresses.
resource management (RM) cell
In ATM networking over ABR connections, a cell that carries congestion
into the network. ABR destinations then turn these cell around. During the
return trip, ABR nodes deposit congestion information in the RM cells. The
source uses the congestion information to influence bandwidth allocation to
ABR VCs and call admission control.
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resource module (RM)
A DPN-100 network backbone device. Resource modules can also serve as
call server resource modules (CSRM).
resource reservation protocol (RSVP)
The primary protocol used for resource reservation in IP networks.
response
Information generated by a component either as a result of some verb being
applied to it or asynchronously to signal some event such as an alarm. A
response can contain several response attributes. For example, the list fs
command is used to list files. It produces many responses, each containing an
attribute to represent the file name, file size, and file modification time.
response attribute
Additional information produced within a response.
response attribute type
The data type of a response attribute.
response attribute value
The value produced as permitted by its type.
restart
The action of reinitializing the software on either a shelf or a card without
reloading that software.
restricted transit node
A node that a call uses for transit, but only in restricted circumstances. A
restricted transit node is free from such restriction when it is used to originate
or terminate a call.
reverse path forwarding (RPF)
Used to select the appropriate incoming interface for a multicast route entry.
RFC 1490
A multiprotocol frame encapsulation method used for carrying data over a
frame relay virtual circuit.
RID
RID/MID routing system
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RID subnet
A group of interconnected Nortel Multiservice Switch nodes that share a
routing identifier (RID).
RIP
RM
1
2
root node
The root node of an ATM PMP call represents the first point of entry into the
network for the PMP call. As a result, this node contains the root of the
multicast tree. For PMP SPVCs, the root node would be the node where the
PMP SPVC is provisioned.
RP
RPF
RP-Set
A set of RP addresses constructed by the BSR based on the list of candidate
RP advertisement messages received by the BSR.
round trip delay (RTD)
The time delay in a round trip from one end of the connection to the other.
route
A list of individual Nortel Multiservice Switch trunks over which a logical
connection exchanges data between two endpoints.
route caching
Route caching is a method of storing and maintaining routing paths for future
use.
route selector (RS)
A Nortel Multiservice Switch network server (routing subcomponent) used for
selecting newly requested or rerouted path oriented routing system routes.
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routing class of service (RCOS)
A set of parameters that describes how a frame is treated while it is being
routed. Examples of these parameters are: priority, reliability, delay, and
throughput.
routing computation
The process of applying a mathematical algorithm to a topology database to
compute routes. Many types of routing computations can be used. The
Dijkstra algorithm is one particular example of a possible routing computation.
routing control channel
routing identifier (RID)
RIDs identify individual Nortel Multiservice Switch RID subnets or DPN-100
resource modules.
routing information protocol (RIP)
This is a routing protocol for finding IP routes between subnets on an internet.
It is intended for use within autonomous systems of limited size.
routing protocol
A protocol used to exchange routing information between peer routing control
processors. The routing information is used to set up routing tables for a
particular address scheme in a network. These tables are used by a packet
forwarding function to forward packets from a network protocol.
routing protocol interface (RPI)
A process that implements a routing protocol. An RPI is part of an external
address plan maintenance system and is used to exchange routing
information with an external network.
routing scope
The routing scope is the highest level in the private network-to-network
interface (PNNI) hierarchy that a path is allowed to reach.
RPI
RS
RSA
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RSI
RSR
RSVP
RTD
rtVBR
S/D
SA
SAD
1
2
SAP
SAR
SBIC
SCB
SCN
scope
Scope defines the level of advertisement for an address in a PNNI network.
The level of advertisement is a level of a peer group in the PNNI routing
hierarchy.
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SCR
SCS
SDS
SDH
SDU
SEC
SDH Equipment Clock.
secondary control bus (SCB)
The secondary control buses enable the processor cards to communicate with
the software embedded on any fabric card. The SCBs also enable any two
processor cards to exchange information, bypassing the fabric cards.
Secure shell (Ssh)
A Secure shell on a Multiservice Switch provides the capability for an operator
to connect to the node in such a way that all authentication information and
subsequent session traffic is encrypted for increased security.
security association (SA)
A dedicated secure virtual connection between two peers.
security association database (SAD)
A database containing the set of all active SAs within a peer.
security parameter index (SPI)
An index established when the security association (SA) is negotiated
between two peers. This index will be used along with peer address and
protocol type to index the right SA in the security association database (SAD)
for inbound traffic.
security policy (SP)
A policy that defines the security services to be applied to a specific IP traffic
flow.
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security policy database (SPD)
A database containing all of the policies that define the security protocols for
all IP traffic flows in and out of a peer.
segmentation and reassembly (SAR) sublayer
A sublayer of an AAL that performs segmentation of the higher-layer PDUs
into ATM cell payloads and receives ATM cell payloads to be reassembled into
higher-layer PDUs.
serialization delay
Serialization delay is the time to clock a frame or cell into or out of a device
(Nortel Multiservice Switch node).
service
A software application. Examples of a Nortel Multiservice Switch service:
frame relay and ATM bearer service.
service access point (SAP)
The service access point of a protocol layer is the point at which an upper
(client) layer requests service from the layer.
service bundle
A Nortel Multiservice Switch feature that packages software for downloading
to the network processing units (NPUs) on a GQM-based FP.
service data unit (SDU)
The entire packet of data received from the immediate upper (client) layer to
be serviced by a protocol layer. The PDU of the client layer is the SDU of the
next lower layer.
service interworking function (SIWF)
1
The FR-ATM SIWF enables frame relay customer-provided equipment
(CPE) to communicate with ATM-capable CPE. The SIWF maintains
standard interworking between frame relay and ATM equipment, and
maps frame relay DLCIs to ATM VCCs on a one-to-one basis. The FR-
ATM service interworking function is based on the FRF.8 standard.
2
service request (SR)
A request for Nortel Networks to fix a problem.
service-specific convergence sublayer (SSCS)
A sublayer of an AAL that adapts the specific requirements of the service
utilizing the AAL to the lower common AAL sublayers.
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serving capacity
One of the traffic parameters used by the CAC algorithm to determine if the
link of the particular node can accommodate a VCC or a VPC connection
point.
SET alarm
An alarm that is issued when a fault condition is detected. These alarms have
an activeListStatus value of “SET”.
SETS
setup priority
In PORS networks, setup priority indicates the relative importance of a
connection, and its tolerance of path bumping. A connection with a lower
setup priority can be bumped to an alternative path or terminated by a
connection with a higher priority.
SFP module
SFQ
SFS
shadowed file system (SFS)
A mass storage file system that retains data on the control processor hard
disks. Data retained by the file system includes software, provisioning data,
and spooled data from the data collection system. The shadowed file system
allows up to two disks to operate in synchronization for redundancy.
shaped fair queuing (SFQ)
A method for smoothing out traffic bursts. SFQ is useful for ensuring that
transmitted egress traffic conforms to subscribed traffic parameters. SFQ
regulates the emission interval of cells in the egress direction.
shared buffer memory
shared bus
A 32-bit bus on a processor card that ties all peripheral devices together. The
shared buffer memory, shared bus interface controller, link controller, and bus
controller are some of the devices that use the shared bus.
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shared bus interface controller (SBIC)
An ASIC used to manage and manipulate queues and blocks within the
shared memory and to coordinate all direct memory access (DMA) into the
shared memory. The queue controller (QC) is part of the SBIC.
shared memory
A common memory pool on a processor card in which all blocks, buffers, and
queues are stored. Frames enter Nortel Multiservice Switch nodes from a
network link to the interfacing function processor where they are stored in
memory. Multiservice Switch software then determines each frame’s
destination. Once destinations are determined, the hardware moves the
frames through the processor card without further software intervention.
Direct memory access into the shared memory is controlled by the shared bus
interface controller.
shared multicast distribution tree
A multicast distribution tree rooted at a well-known point such as an RP
through which receivers hear of new sources and new receivers hear of all
sources.
shelf
Refers to the processor card section, the power converter section, the cooling
unit, and the cable management assembly. The shelf provides power and
communication between processor cards through the backplane.
shelf management system (SMS)
The software system responsible for managing the software and hardware of
the shelf. It consists of three major subsystems: the software control system
(SCS), the bus/backplane control system (BCS) and the processor control
system (PCS).
shortest path first (SPF)
A class of routing protocols that use Djikstra’s algorithm to compute the
shortest path through a network, according to specified metrics, for efficient
transmission of packet data.
shortest path tree (SPT)
A multicast distribution tree created by the merger of all the shortest paths that
connect receivers to the source of the multicast data packets.
short loop
A configuration where there is no AQM on the egress FP.
signaling
The exchange of electrical information specifically concerned with the
establishment and control of connections in a communication network.
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signal processing module (SPM)
A hardware module on the voice services function processor that processes
signaling information.
simple network management protocol (SNMP)
A multivendor standard network management protocol that polls components
in the network, typically over an IP-based network. The protocol data units are
encoded in ASN.1. SNMP concentrates primarily on the observation and
control of the network. It is defined by RFC 1157 and RFC 1213.
single bus mode
A configuration in which only one backplane bus is available to carry cells
between operational cards. The other bus has been taken out of service.
single-ended accounting
Accounting records are generated at only one end of the connection with no
feedback from the other end. This option is available for frame relay and ATM
accounting features. SingleEnd is another term for a single-ended accounting
record for ATM accounting. Due to the lossy nature of ATM networks, double-
ended accounting is recommended for ATM accounting.
single fabric mode
A configuration in which only one backplane fabric card is available to carry
cells between operational cards. The other fabric card has been taken out of
service.
single-FP line APS
1
A type of implementation scheme that uses a single optical interface card
to provide SONET or SDH line automatic protection switching.
2
single-hop BGP
Single-hop border gateway protocol (BGP) refers to a BGP connection
established between peers that are directly connected. See also external
single-mode (SM)
Optical fiber that is capable of propagating light signals of only one
wavelength.
single party node
A network node where the connection is only used for the information flow to/
from a single party of a call.
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SIWF
SM
Small form-factor pluggable optical transceiver module
The small form-factor pluggable (SFP) optical transceiver module is a fiber
optical unit that interfaces between each optical module socket (port) on the
faceplate of a function processor (FP) card and the fiber optical cables with LC
small form connectors. When FPs have SFP modules, each port can have a
different version of the module such that various multimode (MM) and single-
mode (SM) fiber cables and reaches can be appropriately connected to the
same faceplate. SFP modules provide flexible use of an FP’s interfaces for
each port on the card.
SMDS
SMS
SNA
SNMP
SNMP information model
The information model defined for the SNMP protocol. This model represents
management information in terms of scalar and tabular variables. The
definitions of these variables are contained in MIB modules.
SNMPD
Simple network management protocol daemon.
soft rerouting
soft permanent virtual circuit (SPVC, soft PVC)
Soft PVCs support the same functionality as permanent virtual connections
but eliminate the need to manually provision each node along the connection.
The endpoint is provisioned but the connection route is selected automatically.
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soft permanent virtual path (SPVP, soft PVP)
Soft PVPs support the same functionality as a permanent virtual path but
eliminate the need to manually provision each node along the connection. The
endpoint is provisioned but the connection route is selected automatically.
software control system (SCS)
The software system that manages the software installed in a shelf. It controls
the downloading of software, cleans up unused software on the Nortel
Multiservice Switch node disk, and determines which software modules need
to be loaded on each processor card.
software distribution site (SDS)
A workstation designated to manage, store, and provide access to Nortel
Multiservice Switch software.
SONET
SONET payload envelope (SPE)
The user data of a SONET signal.
source/destination
The name of the endpoints of an ABR loop when considered in a given single
direction. ABR requires that a network is divided into ABR loops with a source
and destination at either end of the loop. The direction from source to
destination is the direction of traffic flow. For traffic in the reverse direction, the
source and destination roles are reversed. See resource management (RM)
source node
The node that originates the connection.
source route
In ATM PNNI networking, a route that has been determined by the source
node to the destination node. As a result of this calculation, a source route
includes a complete designated transit list (DTL), which is based on the
distributed topology information that is available at the time the calculation is
made.
source routing
A routing approach in which the source node determines the route to the
requested destination before setting up the call.
SP
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SPT
spare card
A spare processor card is either
•
an installed back-up card that has been configured (provisioned) in
software to take over the traffic and services of a compatible or equivalent
card when that card is removed from service manually or by the system;
in the Nortel Multiservice Switch suite of NTPs, occurrences of “spare
card” almost always refer to this definition
•
an unused card that is stored as a replacement card in the event of a
failure, upgrade, or redeployment of a compatible or equivalent card
sparing
Using a spare card to enable redundant back-up of another card’s active
traffic, services, and capabilities. The effectiveness of the sparing depends on
choosing a compatible or equivalent card. A compatible card usually has the
same root product engineering code (PEC) and provides the same services
and capabilities but with different rates of performance. An equivalent card
can have a different PEC but provides the same or very similar services and
capabilities.
sparing panel
A termination panel that enables the sparing of one or more function
processors (FPs) by a single FP of the same type and compatible or
sparing timer
This timer is used to cause a switchover if a failed main function processor
(FP) in a one-for-n sparing configuration has not recovered by the time it
SPD
SPE
specified path
A manually pre-determined path that consists of a series of transit nodes.
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specified path connection
A connection that is created using a specified path.
speech activity detection (SAD)
A function performed by Nortel Multiservice Switch system when processing
voice calls that saves bandwidth by not transmitting the silent portions of a
conversation. Typical telephone conversations consist of 40 to 60 percent
silence.
SPF
SPI
SPM
spooled statistics
Statistics that are collected by the data collection system (DCS) from various
applications. These statistics are used for network planning and engineering
purposes.
SPVC
1
2
SPVP
1
2
SR
Ssh
S-switched permanent virtual circuit (S-SPVC)
1
A switched SPVC (S-SPVC) is a switched connection at a frame relay
network-to-network interface (NNI) that enables connectivity across
networks between configured SPVC endpoints (P-SPVCs).
2
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stability timer
This timer allows the detection of repetitive main FP card failures and is used
to cause a switchover if a main function processor in a one-for-n sparing
configuration fails within one hour after it starts running as the active FP. See
standard virtual path terminator
A type of virtual path terminator that allows simultaneous traffic management
at both the VP and VC level. Standard virtual path terminators also allow VPs
and VCs on the same interface to dynamically share bandwidth.
standby
Applies to equipment and instances of software that protect the ability to
provide services through redundancy. Standby equipment and software can
state
An operational value indicating the high-level condition of a component. Its
range of values is usually small. For example, the usage state can be idle,
active, or busy, while the amount-used status could vary from 0 percent to 100
percent. State changes can generate alarms or service change notifications.
Status changes can generate alarms when certain thresholds are passed.
state change notification (SCN)
In OSI, a notification of a change of OSI state and status values. In Nortel
Multiservice Switch systems, the notification is generated only by a change in
operational state changes in a preselected set of components. Nortel
Multiservice Data Manager uses SCNs to update the state of components that
are being displayed.
state walk
An activity performed by the Multiservice Data Manager surveillance
infrastructure to obtain or synchronize fault information from a device (for
example, a Nortel Multiservice Switch node).
static_local
A network directly connected to the router in question.
static_remote
A host or route statically defined to the router in question but not directly
connected to the router.
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static route
A static IP route is a provisioned IP route. The provisioning information
includes a destination IP address, subnet mask, cost of the route (metric),
whether it is protected or not, and one or more NextHops on the path to
destination of the IP route
statistic
Nortel Multiservice Switch system has three categories of statistics, which
consist of counters and gauges (for example, byte counts and processor and
link utilization):
•
•
•
statistics for network engineering and long-term planning activities (these
are gathered at regular intervals and are usually processed offline)
real-time statistics for day-to-day troubleshooting activities (these are
required in when problems arise)
statistics for billing and customer reporting activities for each call
statistics collection interval
The 15-minute interval during which spooled statistics are collected. This
interval is based on network time and occurs across the network on the hour
and 15, 30, and 45 minutes past the hour.
status
STM-1
An operational value giving different information than the state value.
Synchronous transport module level 1. Equivalent of STS-3/STS-3c.
stratum-3 clock
Timing sources for networks are often described in terms of stratum levels.
The different stratum clock sources define different levels of accuracy. A
Stratum-3 clock has an accuracy of 1.6 bits in 109.
STS-1
STS-N
Synchronous Transport Signal level 1. The basic logical building block signal
with a rate of 51.840 Mbit/s.
Synchronous Transport Signal level N. The signal is obtained by byte
interleaving N STS-1 signals together. The rate of the STS-N is N times
51.840 Mbit/s.
stub network
An OSPF network with only one OSPF router.
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subcomponent
A component hierarchically named within another (for example, lp/0 v35/0 is
a subcomponent of lp/0).
subnet mask
A method for identifying the subnet field from the host field of an address. This
divides a network into smaller administrative units called subnetworks or
subnets.
successive SET alarm
A SET alarm received while there is an outstanding SET alarm against the
same NTP index and component name.
summary address
In PNNI networking, an address prefix that tells a node how to summarize
sustainable cell rate (SCR)
One of a set of traffic characterization values used to define traffic
characteristics through the traffic descriptor types.
SCR defines the upper bound of the cell rate that can be sustained for a
connection over an indefinite time period. It is used by the network operator to
configure the connection to ensure the QOS defined in the traffic contract.
The five values used in the traffic descriptor parameters are peak cell rate
(PCR), sustainable cell rate (SCR), maximum burst size (MBS), cell delay
variation tolerance (CDVT), and requested shaping rate (RSR).
SVC
1
2
switched multimegabit data service (SMDS)
A set of standards developed by Telcordia for communication over telephone
lines.
switched permanent virtual circuit (SPVC)
A type of virtual circuit (VC) that allows configured SPVC endpoints in two
different frame relay or ATM networks to establish a switched connection
across network-to-network interfaces (NNIs). It is a logical connection for
which endpoints are configured by the network operator but for which the
route is selected automatically.
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A configured SPVC that uses the switched connection between networks is a
permanent SPVC (P-SPVC). The switched connection at the NNI that enables
connectivity between networks is a switched SPVC (S-SPVC).
See also:
1
2
3
switched permanent virtual path (SPVP)
A a type of virtual path (VP) that allows configured SPVP endpoints in two
different frame relay or ATM networks to establish a switched connection
across network-to-network interfaces (NNIs). It is a logical connection, the
endpoints of which are configured by the network operator, but with a route is
selected automatically at call setup.
A configured SPVP that uses the switched connection between networks is a
permanent SPVP (P-SPVP). The switched connection at the NNI that enables
connectivity between networks is a switched SPVP (S-SPVP).
See also:
•
•
•
switched virtual channel (SVC), ATM networking
1
A virtual channel connection that is dynamically established and ended
through control signaling. The user defines the endpoints when the call is
initiated.
2
switched virtual circuit (SVC)
1
A type of virtual circuit (VC) that is established and torn down by
subscriber applications on an as-needed basis. It is a logical connection
that remains in place only for the duration of data transfer. User equipment
signals the desired destination, and the connection route is selected
automatically through SVC signaling.
2
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switched virtual path (SVP)
1
A type of virtual path (VP) that is established and torn down by subscriber
applications on an as-needed basis. It is a logical connection that remains
in place only for the duration of data transfer. User equipment signals the
desired destination, and the connection route is selected automatically
through SVP signaling.
2
switched voice
1
A Nortel Multiservice Switch 7400 node feature in which TDM traffic from
a narrowband network is terminated at a Multiservice Switch 7400 node
and dynamically routed over the ATM network.
2
switchover
symmetric encryption
A key is symmetric when both peers use the same private key, ensuring
security.
synchronous digital hierarchy (SDH)
The international version of the Telcordia SONET standard, based on STM-1
frame. The basic line rate is 155.52 Mbit/s. SDH is defined by ITU-T.
synchronous equipment timing source (SETS)
synchronous optical network (SONET) standard
A ultra-high-speed fiber-optic transmission standard developed by Telcordia
for fiber-based digital transmission networks. SONETV is the North American
version of SDH and is based on STS-1.
System Network Architecture (SNA)
A proprietary network architecture developed by IBM. SNA shares some
characteristics with the OSI reference model.
T1
T3
Timing signal derived from an external 2 MHz (or 2 Mbit/s, no payload)
synchronization interface.
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T4
Timing towards a 2 MHz (or 2 Mbit/s, no payload) synchronization interface.
tag control information (TCI)
Tag control information (TCI) is a subheader of the IEEE 802.1Q tag header.
It consists of two octets encoded with user-priority bits, a canonical format
indicator field, and a VLAN identifier.
tag protocol identifier (TPID)
Tag protocol identifier (TPID) is a subheader of the IEEE 802.1Q tag header.
It consists of two octets encoded with the 802.1Q tag type for VLANs. The
format of the encoding is dependent on the type of encoding supported: SNAP
or Ethernet.
tandem node
A node between the ingress and egress nodes that decides independently the
best packet forwarding route to the egress node identified in the packet. See
tandem pass through (TPT)
A software process that allows MVP-E FPs on tandem Nortel Multiservice
Switch nodes to dynamically detect each other and pass, without modification,
compressed voice data through an intermediate voice switch. Voice Transport
and Voice Networking support TPT.
TC
TCI
TCP
TDM
TDMA
TDP
TDS
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TDT
Telnet
A terminal access protocol for accessing remote devices over an IP-based
network. The protocol provides support for various types of terminals and is
typically found in IP- or UNIX-based environments.
To establish a Telnet connection, you need both a Telnet client and a Telnet
server. The Telnet client resides on the local device and connects to the Telnet
server on the remote device. Nortel Multiservice Switch nodes act as both a
Telnet server (for incoming Telnet connections) and a Telnet client (for
outgoing Telnet connections).
termination panel.
A panel used for cable distribution.
TFTP
time-division multiple access
A technique originated in satellite communications to interweave multiple
conversations into one transponder so as to appear to get simultaneous
conversations. TDMA is a variation on TASI (time assignment speech
interpolation). TDMA is now used in cellular and other wireless
communications.
time-division multiplexing (TDM)
A method of transmitting digital signals from multiple sources in series on the
same line.
Time Management System (TMS)
Nortel Multiservice Switch system responsible for maintaining
•
•
•
the calendar time on the network
the processor time during rebooting of the FP or CP
the module time (maintaining synchronization between, for example, an
FP and a CP)
time-of-day accounting (TODA)
Time-of-day accounting allows for accounting records to be generated up to
24 times for each day. TODA entries must be a minimum of one hour apart and
a maximum of 12 hours apart. The DCS-managed table holding 24 entries
manages this accounting feature. When TODA is enabled the system is in
TODA mode. A TODA changeover occurs whenever the actual time of day
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timer-mode accounting
When TODA is disabled, an accounting record is generated every 12 hours for
each connection.
TM
TMS
TODA
topology maintenance
A software system that performs network topology discovery and
maintenance for the Nortel Multiservice Switch node.
topology region
A group of interconnected Nortel Multiservice Switch nodes that share
topological routing information.
topology database
The database that describes the topology of the entire PNNI routing domain
as seen by a node. Each node that participates in a PNNI network maintains
a topology database.
topology metric
A generic term that refers to either a link metric or a nodal metric.
tos
TPID
TPT
trace connection
A new signaling message used by the trace source node to initiate the
connection trace feature.
trace connection acknowledge
A new signalling message used by the trace destination node to acknowledge
the trace connection message.
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trace destination interface
The interface on which a path or connection trace terminates when it
completes normally.
trace destination node
The node that terminates the path or connection trace for a given connection
and has an outgoing trace destination interface.
trace source interface
The interface at the trace source node that is designated as the starting point
for the path or connection trace of a given connection.
trace source node
The node that initiates the path or connection trace for a given connection.
trace transit list (TTL) information element
An identifier added to the signaling messages to collect trace information.
traffic contract
The agreement that specifies the required transfer characteristics for an ATM
connection.
traffic descriptor parameter (TDP)
There are five parameters that are used to define a traffic descriptor type
(TDT). Taken together with the QOS, these parameters specify the traffic
characteristics of an ATM connection.
The five values used in the traffic descriptor parameters are peak cell rate
(PCR), sustainable cell rate (SCR), maximum burst size (MBS), cell delay
variation tolerance (CDVT), and requested shaping rate (RSR).
traffic descriptor type (TDT)
Traffic descriptor types define which traffic descriptor parameters are applied
to a connection. Types are defined in the ATM Forum 3.0/3.1 and 4.0
standards. Nortel Multiservice Switch system also incorporates proprietary
parameters that are used in traffic shaping, CAC, and UPC.
traffic management (TM)
A set of mechanisms in hardware and software that enhance the availability
of bandwidth to connections that absolutely require it and prevent the
overloading of networks to prevent data losses.
traffic shaping
A method used to smooth out traffic bursts by regulating the emission interval
of cells or frames in the transmit direction. This is useful for ensuring
conformance of transmitted traffic to subscribed traffic parameters.
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transit network
An OSPF network with more than one router.
transit node
A logical representation of a node, which is also known as a hop node. It is
composed of an address called node ID and an egress port called port ID.
translation mode
One of two modes of the FR-ATM interworking service. When translation
mode is chosen for a PVC, the FR-ATM interworking function performs the
mapping of upper layer protocol encapsulations between the two incompatible
encapsulation methods. Translation mode allows the carriage of multiple
upper layer user protocols over the same PVC and the interworking of routed
protocols between a frame relay CPE and a B-ISDN CPE.
transmission control protocol (TCP)
A connection-oriented transport-layer protocol that provides reliable, robust,
and adaptable data transfer between end system upper-layer protocols (ULP).
TCP assumes that simple, potentially unreliable, datagram services are
available from lower-level protocols. TCP is defined in RFC 793.
trap
An unsolicited message from an agent to a manager containing information
about an exceptional event in that agent.
TRM
transparent data service (TDS)
A service offered on Nortel Multiservice Switch nodes that allows the user to
send bit or HDLC data across the network without interpretation. See also bit-
transport resource manager (TRM)
A base routing system that acts as an intermediary between links and routing
systems. All Nortel Multiservice Switch trunks and DPN gateways on the
Multiservice Switch node are grouped into link groups by TRM and are
presented to the address plan managers (for example, topology and DPN
EAP) that use them. TRM is also involved in the multiplexing of logical network
numbers on the links. A third function of TRM is to maintain the link and link
group packet forwarding tables on all processors in a Multiservice Switch
shelf. TRM also directs some of the maintenance of forwarding tables for
various address plans on the FPs of the module.
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trivial file transfer protocol (TFTP)
A protocol that governs transferring files between nodes without protection
against packet loss.
trunk
The generic term for a physical connection, not a Nortel Multiservice Switch
network-specific term.
trunk conditioning (TC)
A technique whereby a constant bit pattern is applied to specific time slots to
indicate downstream that the system has detected a fault in the upstream data
path.
trunking (acknowledged)
The receiving node confirms the quality of the received packets and requests
retransmission of corrupted packets.
trunking (unacknowledged)
The receiving node does not acknowledge the receipt of packets.
TTC2M
Japanese Telecommunication Technology Committee 2 Mbit/s PBX-TDM
interface, referencing TTC JJ-20.10, JJ-20.11, JJ-20.12.
tunneling
A protocol encapsulation process that embeds propriety protocols, such as
MPANL, into a carrier protocol, such as frame relay.
Type 2.1 (T2.1) node
A local exchange node (LEN) node.
type of service
The 8-bit field in an IP packet header used for specifying differentiated service
parameters for the IP packet. The 6 most significant bits of this field are also
U-plane
In frame relay, the data transfer protocol or U-plane is the protocol used for the
transfer of the actual user data. The protocol is based on T1.618, which is
based on a subset of ANSI T1.602 (LAPD). For more information, see
NN10600-900 Nortel Multiservice Switch 7400/15000/20000 Frame Relay
Technology Fundamentals.
UBR
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UBR with MDCR
UDP
UMTS
UNI
UNI scope
The membership scope associated with group addresses.
unicast forwarding
A packet forwarding mode that delivers the packet to a single destination
(egress node).
Universal Mobile Telecommunications System
A third-generation, CDMA-based, wireless system designed for
interoperability with existing TDMA-based GSM/GPRS networks. UMTS
standardizes low-power, short-distance radio transmissions, such as cellular,
cordless, low-end wireless, local area network, private mobile radio and
paging systems.
universal trunk protocol (UTP)
The specific protocol between Nortel Multiservice Switch and DPN devices
through an acknowledged trunking system.
unspecified bit rate (UBR)
A service category that defines connection throughput as best-effort, in which
cells are either forwarded if link bandwidth is available or discarded if
bandwidth is not available. UBR traffic has low emission and high discard
eligibility. This QOS is used for non real-time applications.
unspecified bit rate (UBR) with minimum desired cell rate (MDCR)
A standards-based type of UBR service category in which a preference for
minimum bandwidth objective is indicated to the network, without defining any
quality of service (QOS) commitment.
UPC
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uplink
An uplink is a logical link representing the connectivity from a border node to
an upnode. Uplinks are the basis for horizontal links between nodes.
upnode
An upnode is the node that represents a border nodes’s outside neighbor in
the common peer group. It must be a neighboring peer of one of the border
node’s ancestors.
usage parameter control (UPC)
A traffic management strategy that enforces traffic characteristics at network
access points. UPC evaluates a connection’s traffic characteristics based on
the traffic descriptor parameters for that connection, and discards or tags non-
conforming cells.
user datagram protocol (UDP)
A simple datagram protocol. UDP is layered directly above the Internet
protocol (IP). This protocol does not provide for acknowledging packets or
error checking. It has a high data rate but is unreliable for accurately delivering
packets.
user-to-network interface (UNI)
1
The frame relay service is provided through a standard interface between
the user device and the network, called the user-to-network interface. For
more information, see the document NN10600-900 Nortel Multiservice
Switch 7400/15000/20000 Frame Relay Technology Fundamentals.
2
An interface between ATM user equipment and ATM network equipment.
UTC
UTP
UTP
V.11
Unshielded twisted pair (a type of cable).
A ITU-T standard that specifies electrical signal levels for data interfaces. V.11
is used by many physical interfaces such as V.36, V.37, RS-449, and X.21.
Nortel Multiservice Switch system V.11 FP provides an X.21 physical
interface.
V.35
A standard ITU-T DCE-DTE physical interface for data communication.
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V5.2
An interface specification defined in the ETSI EN 300 324-1 and
ETSI EN 300 347-1 standards. A V5.2 interface connects a local exchange in
a PSTN network to a number of remote end users.
variable
The field in a component name that can be used to store an attribute. The
attribute denotes the external representation of a variable. A variable is the
internal representation of an attribute.
variable bit rate (VBR)
VBD
VBR
VBR shaping
VC
1
2
VCC
VCI
VCL
VC ping
A command used to determine the path of a frame relay VC or the round trip
VCS
VGCP
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verb
The command or action to be applied to a component. Verbs take options and
produce responses. For example, the delete verb removes a component from
the edit view.
VID
view
A database used to store provisioning data. The current view contains the
current data. The edit view contains data used to edit the current view. The
committed view contains information used in case of a restart or reset.
Vintage 4
Version of accounting records that are generated by DPN modules.
Vintage 4 Enhanced
Vintage 4 accounting records that are used for frame relay. These accounting
records contain different fields for frame relay.
VIPR
virtual channel (VC), ATM networking
In ATM networking, a concept that describes unidirectional transport of ATM
cells associated by a common unique identifier value called VCI.
virtual channel connection (VCC)
In ATM networking, a concatenation of virtual channel links that extends
between two points where the adaptation layer is accessed.
virtual channel identifier (VCI)
In ATM networking, a field in the ATM cell header that identifies the virtual
channel with which the cell is associated.
virtual channel link (VCL)
A segment of virtual channel between two contiguous ATM layer entities that
process the cells of a virtual channel. A VCL is identified only by the VCI value
in the cell header if it is part of a VPC, or by both the VPI and VCI values if it
is not part of a VPC.
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virtual circuit (VC), frame relay networking
In frame relay networking, the equivalent of a physical connection to a
destination address using shared facilities. Virtual circuits can be permanent
(PVC) or switched (SVC). The virtual circuit is anchored in the function
processors that are connected to the end user devices.
Virtual Circuit System (VCS)
The software system that allows Nortel Multiservice Switch networks to offer
virtual circuits.
virtual interface
In ATM networking, an interface that is configured under a virtual path
terminator, permitting multiple virtual interfaces under a single port. This
configuration contrasts with actual or real interfaces that have a one-to-one
correspondence with a physical port. Virtual interfaces, like their actual
interface counterparts, can be any of UNI, IISP, AINI, or PNNI interfaces. Also
known as virtual UNI or VUNI, virtual IISP or VIISP, virtual AINI or VAINI, and
virtual PNNI or VPNNI.
virtual IP router (VIPR)
Virtual IP router (VIPR) is an IP service that provides basic IP routing in a flat
IP network.This service is also referred to as Basic IP.
virtual LAN (VLAN)
IEEE 802.1Q Ethernet virtual LAN (VLAN) is a subset of the active topology
of a Bridged LAN. A VID is associated with each VLAN.
virtual link (VL)
An IMA virtual link refers to the combination of multiple physical links that use
the inverse multiplexing process to transmit traffic across these links. A virtual
link is presented as a single link to the ATM layer. A VL originates on one FP
running the IMA feature and terminates on another FP running the IMA
feature. Typically, these two FPs are on two different Nortel Multiservice
Switch nodes. Any virtual link can consist of a maximum of eight DS1/E1
physical links on an FP running IMA.
Virtual Media (VM)
Virtual Media (VM) is a Nortel Networks proprietary, hardware independent
broadcast medium. VM is not associated with a physical port but rather a
logical interface.
virtual path (VP)
In frame relay, the equivalent of a physical connection to a destination address
using shared facilities. Virtual paths can be permanent (PVP) or switched
(SVP). The virtual path is anchored in the function processors that are
connected to the end user devices.
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In ATM networking, a unidirectional transport of ATM cells belonging to virtual
channels that are associated by a common identifier value called VPI.
virtual path connection (VPC)
A logical association among, or a group of, virtual channels that have the
same traffic characteristics and follow the same path in a network.
In ATM networking, a concatenation of virtual path links that extends between
the point where the virtual channel identifier values are assigned and the point
where those values are translated or removed.
virtual path connection identifier (VPCI)
In ATM networking, a connection identifier that the nodes at the ends of a
connection over virtual interfaces can use to establish a common identifier
from end to end. In non-associated and VP-associated signaling, the VPI has
the same value as the VPCI.
virtual path identifier (VPI)
A field in the ATM cell header that identifies the virtual path the cell is
associated with. Also, a VPI can form part of the identity of the virtual channel.
virtual path link (VPL)
A segment of a virtual path between two contiguous ATM layer entities that
process the cells of a virtual path, without unbundling the individual virtual
channels that comprise the virtual path. A virtual path link is identified by a
unique VPI value in the cell header.
virtual path termination CAC (VPT-CAC)
A connection admission control (CAC) technique that applies to VCCs under
a virtual path terminator. Compare with ATM interface CAC (AtmIf-CAC).
virtual path terminator (VPT)
An ATM network entity that unbundles a VPC into its VCC elements for
processing. There are two types of VPTs: basic and standard.
virtual private network (VPN)
virtual router (VR)
A common set of interfaces and support mechanisms for the IP protocol.
virtual router access point (VRAP)
A point of access to a VirtualRouter component that defines the IP logical
interface. This logical interface defines the subnet to which the IpMConn or
Control subcomponent is connected.
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virtual router redundancy protocol (VRRP)
A protocol that specifies an election protocol that dynamically assigns
responsibility for a virtual router to one of the VRRP routers on a LAN.
virtual router redundancy protocol backup (VRRP backup)
The set of VRRP routers available to assume forwarding responsibilities for a
virtual router should the current master router fail.
virtual router redundancy protocol MAC address (VRRP MAC address)
A unicast MAC address associated with each VRRP virtual router that is used
as a source MAC address for the VRRP advertisements. The VRRP master
uses this address instead of its physical MAC address in all communications,
for example: ARP response.
virtual router redundancy protocol master (VRRP master)
The VRRP router that assumes the responsibility of forwarding packets sent
to the IP address(es) associated with the virtual route and answers ARP
requests for these IP addresses.
virtual router redundancy protocol router (VRRP router)
A virtual router that runs the virtual router redundancy protocol. This virtual
router may have more than one instance of VRRP provisioned.
virtual source/virtual destination (VS/VD)
The endpoints of the shortened loops. ABR relies on circuit loops with source
and destination nodes to originate and turnaround resource management
cells. Service providers can subdivide an ABR circuit into short loops as a way
to reduce loop length or to avoid non-ABR nodes. The endpoints of the
shortened loops are known as virtual sources and destinations.
virtual UNI
VL
VLAN
VLAN-tagged
A tagged frame whose IEEE 802.1Q-tag carries both VLAN identification and
priority information.
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VLAN identifier (VID)
A VLAN identifier (VID) is a 12-bit field in the TCI subheader of the
IEEE802.1Q tag header.
VM
voice band data (VBD)
Modulated data calls, typically fax and modem calls, carried on a voice
connection.
voice compression
The process of electronically modifying a 64-kbit/s voice channel to obtain a
channel of 32 kbit/s or less for the purpose of increased efficiency in
transmission.
voice gateway control protocol (VGCP)
A Nortel Networks proprietary version of the simple gateway control protocol
(SGCP). VGCP is one possible control interface between the media gateway
controller and the Media Gateway. (VGCP is also known as ASPEN).
voice networking
A service that allows the user to dynamically interconnect voice switches,
such as PBXs, through SVCs.
voice networking call server (VNCS)
The voice networking call server is a database which provides routing and
voice profile information, based on the dialed number, to PORS during voice
networking SVC establishment.
VoIP
voice over frame relay
A Nortel Multiservice Switch system encapsulation protocol that manages
prioritized egress queues and repackages payload frames to assure the
dominance of multimedia (dominantly voice) traffic over application data
traffic. Large data frames are fragmented to avoid multimedia delays and link
frames are packed with data fragments to assure optimal link bandwidth
usage.
voice over Internet Protocol (VoIP)
Voice traffic over an IP network using ATM or Ethernet transport capabilities.
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voice processing module (VPM)
A hardware module on the voice services function processor that processes
voice and voice band data.
voice profile (VP)
A collection of parameters used in voice networking SVC establishment to
define the quality of service for a particular call, depending on the dialed
number.
voice service
Voice service allows you to interconnect voice switches, such as PBXs. It
offers integral voice compression, echo cancellation, FAX handling, and
speech activity detection (SAD).
voice services processor (VSP)
A two-slot FP that provides voice and voice band data processing functionality
between an ATM and a TDM data path. It supports switched or non-switched
voice gateway services.
voice transport
A service that allows the user to interconnect voice switches, such as PBXs,
through PVCs. It offers integral voice compression, echo cancellation, FAX
handling, and speech activity detection (SAD).
VP
VPC
VPCI
VPI
VPL
VPM
VPN
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VPN extender (VpnXc)
A special server card that increases the scalability of IP VPN services. It has
its own dedicated processor and memory and acts as the IP VPN control
plane, hosting all IP VPN virtual routers.
VpnXc
VPT
VPT-CAC
VR
VRAP
VIPR
VRRP
VRRP backup
VRRP MAC address
VRRP master
VRRP router
VS/VD
VSP
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VTDS
VUNI
Voice transparent data service. See transparent data service (TDS)
waiting delay
The time a frame or cell waits in a transmission queue before it gets
transmitted.
WAN
warm standby
Warm standby applications reduce service outages during an FP or CP
switchover. During an equipment switchover, warm standby applications incur
a longer outage of service than hot standby applications, but not as long as
cold standby applications. As well, all connections must be reestablished.
WFQ
weight limited FIFO algorithm (WLFA)
A Nortel Multiservice Switch system proprietary implementation of weighted
fair queuing (WFQ), a non-shaping intra-class scheduler. WLFA is a
mechanism for deciding which cells arriving at a Multiservice Switch node
over individual circuits are delivered next to the common FIFO (first-in-first-
out) trunk queue. WLF works by giving more common queue space to circuits
that have a higher priority. The allocation of queue space effectively assures
higher priority cells a greater share of trunk bandwidth.
weighted random early detection (WRED)
A mechanism for discarding packets based on a weighted random decision
only after the node exceeds a minimum VC queue-length threshold. The node
determines weights according to the extent to which the queue-length
threshold is exceeded with respect to a defined maximum threshold. WRED
is a method for early congestion detection, useful to window-based protocols
(for example, TCP).
wide area network (WAN)
A network used for data communications among widely distributed
geographic sites (bigger than a MAN). Technologies used include leased
lines, connecting routers, multiplexers, packet switches, voice switches, and
products such as Nortel Multiservice Switch nodes.
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wild-carded binary-coded decimal (BCD)
The binary-coded decimal data type with the addition of the ? character to
represent any possible value.
wildcard pattern
A wildcard pattern consists of a character string, with one or more wildcard (*)
characters, where * matches zero or more characters.
wildcarding
Using the asterisk (*) wildcard character or a wildcard pattern to match more
than one component. Type wildcarding replaces the component type with an
asterisk to give all subcomponents of a component. Instance wildcarding
replaces the instance value with an asterisk or wildcard pattern to return
selected instances of a component type.
Wildcarding is available on the display, list, and find commands.
WLFA
WRED
X.25
The ITU-T and ISO-recommended multipoint connection-oriented service that
uses either permanent virtual circuits (PVC) or switched virtual circuits (SVC)
over a physical link. It uses HDLC framing to separate frames.
X.25 gateway
An X.25 access service, consisting of one or more links, connected to another
network.
X.75 gateway
An X.75 access service, consisting of one or more links, connected to another
network.
X.121
The ITU-T recommended numbering plan that includes the numbering plan for
public switched data networks.
XID
XID is an Unnumbered Exchange Identification command/response frame
used to convey the types of LLC services supported by peer link stations
during connection establishment phase.
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XNTP
xPD
A Nortel Multiservice Switch system feature that controls the setting of
network time.
A generic term for any of a number of packet discard algorithms (for example,
EPD, PPD, WRED).
Y-Protection
A Y-protection configuration enables two matched fiber optical FPs to have
hitless equipment protection (EP) and hitless software migration (HSM) while
the far-end interface does not support automatic protection switching (APS) or
multiplex section protection (MSP). The capability is achieved through
software control of hardware lasers firing through custom-made cable
assemblies that split the transmit and receive signals to and from the pair of
FPs to a single interface.
Y-splitter cable
A Y-splitter cable is a fiber optical cable with each transmit and receive fiber
physically split into two. A pair of duplex single-mode (SM) Y-splitter cables is
required for each pair of ports on a pair of Nortel Multiservice Switch 15000 or
Multiservice Switch 20000 node function processors (dual FPs) that are
configured in software to use Y-protection.
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Nortel Multiservice Switch 7400/15000/20000
Terminology
Copyright © 2006 Nortel.
All Rights Reserved.
Publication: NN10600-005
Document status: Standard
Document issue: 7.2S1
Document date: March 2006
Product release: PCR7.2 and up
Job function: Product Fundamentals
Type: NTP
Language type: U.S. English
NORTEL, the globemark design, and the NORTEL corporate logo are
trademarks of Nortel.
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