Nortel Versalar 15000 User manual

Nortel Multiservice Switch 7400/15000/20000
Terminology
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
Copyright © 2006 Nortel.
All Rights Reserved.
NORTEL, the globemark design, and the NORTEL corporate logo are trademarks of Nortel.

Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
Contents
What’s new 4
Secure shell (Ssh) on Nortel Multiservice Switch 15000 and 20000 4
Load Re-balancing on Parallel Links 4
List of terms 5

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:
•Secure shell (Ssh) on Nortel Multiservice Switch 15000 and 20000
(page 4)
•Load Re-balancing on Parallel Links (page 4)
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:
•component model (page 32)
•Internet protocol interface over virtual circuit (IPIVC) (page 67)
•network management interface (NMIF) (page 88)
The following terms were added for this feature:
•Secure shell (Ssh) (page 118)
•Ssh (page 126)
Load Re-balancing on Parallel Links
The following term was added for this feature:
•LRB (page 78)

Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
List of terms
802.3
An IEEE standard defining Ethernet communications.
AAL
See ATM adaptation layer (AAL) (page 12).
AAL1
See ATM adaptation layer type 1 (AAL1) (page 13).
AAL2
See ATM adaptation layer type 2 (AAL2) (page 13).
AAList
See active alarm list (page 7).
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
See ATM adaptation layer type 5 (AAL-5) (page 13).
A-bit signaling
See availability-bit signaling (page 16).
ABR
1 See area border router (ABR) (page 11).
2 See available bit rate (ABR) (page 16).
ABS
See ATM bearer service (ABS) (page 13).

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List of terms
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
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
See access call control (ACC) (page 6).
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)
(page 30).
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
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
ACR
See available cell rate (ACR) (page 16).
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
makes scaling in large networks possible. See summary address (page 129).

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List of terms
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
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
See adaptive differential pulse code modulation (ADPCM) (page 7).
ADTF
See allowed cell rate decrease time factor (ADTF) (page 9).
advertisement scope
See address scope (page 7).
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
See ATM inter-network interface (AINI) (page 13).
AIR
See allowed information rate (AIR) (page 9).
AIS
See alarm indication signal (AIS) (page 9).

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List of terms
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
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 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.
2 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.
See also mu-law (page 83).
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
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
Copyright © 2006, Nortel Nortel Confidential
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
applied to the processor card that contains the bus tap. See also clock master
(page 28).
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
See access module (AM) (page 6).
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
See alternate mark inversion (AMI) (page 10).
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
See adjacent network identifier (ANID) (page 8).
ANSI
See American National Standards Institute (ANSI) (page 10).