Glossary

glossary

A

ABR

Available Bit Rate is a Class of Service defined for ATM connections by the ATM Forum. Devices using ABR are guaranteed no more than a certain rate of throughput. This rate dynamically changes and the current value is relayed to the sending device by way of Resource Management (RM) cells.

AESA

ATM End Station Address. The 19-octet address that uniquely identifies each logical node.

Annex G

A bidirectional protocol, defined in Recommendation Q.2931, used for monitoring the status of connections across an UNI interface. The BPX SES PNNI controller uses the Annex G protocol to pass connection status information between a itself and the BPX 8600 switch.

C

CBR

Constant Bit Rate is used by connection that request a static amount of bandwidth, for continuous availability during the connection lifetime. The amount of bandwidth is characterized PCR.

Class of Service (CoS) Buffer

A buffer or queue which serves connections with similar QoS requirements.

Class of Service (CoS) Buffer Descriptor Template

A component of a Service Class Template which contains Class of Service Buffer configurations indexed by CoSB number.

Community

In the context of SNMP, a relationship between an agent and a set of SNMP managers that defines security characteristics. The community concept is a local one. defined at the agent. The agent establishes one community for each desired combination of authentication, access control, and proxy characteristics. Each community is given a unique (within this agent) community name, and the management stations within that community are provided with and must employ the community name in all get and set operations. The agent may establish a number of communities, with overlapping management station membership.

D

DCC

Data Country Code.

DTL

Designated Transit List.

E

Enterprise MIB

A MIB module defined in the enterprise-specific portion of the Internet management space.

F

Feeder

A Feeder is a small switch which acts as an extension shelf, typically with lower-bandwidth interfaces, for a larger switch. The larger switch is referred to as the Routing Node for the Feeder(s).

I

ICD

International Code Designator.

IISP

Interim Inter-switch Protocol.

ILMI

Integrated Local Management Interface.

L

LCN

Each interface card in a switch has a certain number of Logical Connection Numbers. A Logical Connection Number is used for each cross connect leg through the card in question. "LCN" is often roughly synonymous with "cross connect leg". In VSI terminology, and LCN is an example of an Other End Reference.

LGN

Logical Group Node.

Logical Interface

Each physical interface and every virtual trunk endpoint on a platform is represented to the VSI Controllers as a different Logical Interface with partitions, and other VSI configuration. Logical Interface numbers are 32-bit with a format which is, in general, known only to the platform.

Logical Link

Either a physical link or a VPC PVC across another ATM network. Logical links are referred to as horizontal links (if connecting logical nodes within a pair) or outside links (if connecting peer groups).

M

Managed device

A device containing a network management agent implementation.

MBS

Maximum Burst Size.

MIB

Management Information Base, a structured set of data variables, called objects, in which each variable represents some resource to be managed.

MIB-II

Internet-standard MIB, RFC 1213.

N

nrtVBR

Non-real-time-variable-bit-rate is intended for non-real-time application that have bursty traffic characteristics, and which are characterized in terms of a PCR, SCR, and MBS.

NSAP

Network Service Access Point.

NIC

Network Interface Card. An ATM card for a host or router is an ATM NIC.

O

Object

In the context of SNMP, a data variable that represents some resource or other aspect of a managed device.

Object type

Defines a particular kind of managed object. The definition of an object type is therefore a syntactic description.

P

PCR

Peak Cell Rate

PGL

Peer Group Leader.

PNNI

Private Network-to-Network Interface.

PNNI RCC

PNNI routing control channel. See RCC.

Port

The VSI makes no distinction between trunk ports and end-point ports. "Port" is synonymous with "Interface".

PTSE

PNNI Topology State Element.

PXM

Processor Switch Module.

R

RCC

Routing control channel. A VCC used for the exchange of PNNI routing protocol messages.

RFC

Request For Comment.

Routing Node

In tiered networks terminology, a Routing Node is a larger switch to which one or more Feeders is attached.

rtVBR

Real-time-variable-bit-rate is intended for real-time applications that require tightly constrained delay and delay variation (such as voice and video applications). rtVBR is characterized by PCR, SCR, and MBS.

S

Service Class (aka Service Type, or Service Category)

A concept for grouping connections that share a common set of traffic characteristics and QoS requirements.

Service Class database

The collection of data items which support the Service Class Template concept.

Service Class Template (SCT)

A set of data structures which map ATM Service Types to sets of pre-configured communication parameters.

SCR

Sustainable Cell Rate.

SNMP

Simple Network Management Protocol.

SVC

Switched Virtual Circuit.

SPVC

Soft Permanent Virtual Circuit.

U

UBR

Unspecified Bit Rate is intended for non-real-time application, such as those that do not require tightly constrained delay and delay variation. Traffic in the UBR class is not guaranteed any particular throughput or delay performance. In this regard, UBR is similar to `traditional' IP service.

UNI

User-to-Network Interface.

V

VC

ATM and Frame Relay traffic is carried in Virtual Channels which are set up between adjacent ATM or Frame Relay switches before data transmission occurs. An ATM link between switches may support up to 2²⁸ different VCs, although a small number of VCs is reserved for special purposes.

VCC

Traffic is carried end-to-end on an ATM network on Virtual Channel Connections, which consist of a sequence of Virtual Channels between switches linked by VC cross-connects at the switches.

VCI

Each VC within a specific Virtual Path on a link has a unique Virtual Channel Identifier, which is a 16-bit number (see also VPCI).

VP, VPC, VPI

A Virtual Path is a `bundle' of 2¹⁶ Virtual Connections with the same Virtual Path Identifier, i.e. the first 12 bits of the VPCI. Most ATM switches can switch VPs using only a single cross-connect (instead of up to 2¹⁶). An end-to-end sequence of VPs cross-connected at the intermediate switches is a Virtual Path Connection.

VPCI

Each VC on a link has a unique Virtual Path and Channel Identifier, which is a 28-bit number. The VPCI consists of a 12-bit VPI concatenated with a 16-bit VCI.

A
ABR	Available Bit Rate is a Class of Service defined for ATM connections by the ATM Forum. Devices using ABR are guaranteed no more than a certain rate of throughput. This rate dynamically changes and the current value is relayed to the sending device by way of Resource Management (RM) cells.
AESA	ATM End Station Address. The 19-octet address that uniquely identifies each logical node.
Annex G	A bidirectional protocol, defined in Recommendation Q.2931, used for monitoring the status of connections across an UNI interface. The BPX SES PNNI controller uses the Annex G protocol to pass connection status information between a itself and the BPX 8600 switch.

C
CBR	Constant Bit Rate is used by connection that request a static amount of bandwidth, for continuous availability during the connection lifetime. The amount of bandwidth is characterized PCR.
Class of Service (CoS) Buffer	A buffer or queue which serves connections with similar QoS requirements.
Class of Service (CoS) Buffer Descriptor Template	A component of a Service Class Template which contains Class of Service Buffer configurations indexed by CoSB number.
Community	In the context of SNMP, a relationship between an agent and a set of SNMP managers that defines security characteristics. The community concept is a local one. defined at the agent. The agent establishes one community for each desired combination of authentication, access control, and proxy characteristics. Each community is given a unique (within this agent) community name, and the management stations within that community are provided with and must employ the community name in all get and set operations. The agent may establish a number of communities, with overlapping management station membership.

E
Enterprise MIB	A MIB module defined in the enterprise-specific portion of the Internet management space.

F
Feeder	A Feeder is a small switch which acts as an extension shelf, typically with lower-bandwidth interfaces, for a larger switch. The larger switch is referred to as the Routing Node for the Feeder(s).

I
ICD	International Code Designator.
IISP	Interim Inter-switch Protocol.
ILMI	Integrated Local Management Interface.

L
LCN	Each interface card in a switch has a certain number of Logical Connection Numbers. A Logical Connection Number is used for each cross connect leg through the card in question. "LCN" is often roughly synonymous with "cross connect leg". In VSI terminology, and LCN is an example of an Other End Reference.
LGN	Logical Group Node.
Logical Interface	Each physical interface and every virtual trunk endpoint on a platform is represented to the VSI Controllers as a different Logical Interface with partitions, and other VSI configuration. Logical Interface numbers are 32-bit with a format which is, in general, known only to the platform.
Logical Link	Either a physical link or a VPC PVC across another ATM network. Logical links are referred to as horizontal links (if connecting logical nodes within a pair) or outside links (if connecting peer groups).

M
Managed device	A device containing a network management agent implementation.
MBS	Maximum Burst Size.
MIB	Management Information Base, a structured set of data variables, called objects, in which each variable represents some resource to be managed.
MIB-II	Internet-standard MIB, RFC 1213.

N
nrtVBR	Non-real-time-variable-bit-rate is intended for non-real-time application that have bursty traffic characteristics, and which are characterized in terms of a PCR, SCR, and MBS.
NSAP	Network Service Access Point.
NIC	Network Interface Card. An ATM card for a host or router is an ATM NIC.

O
Object	In the context of SNMP, a data variable that represents some resource or other aspect of a managed device.
Object type	Defines a particular kind of managed object. The definition of an object type is therefore a syntactic description.

P
PCR	Peak Cell Rate
PGL	Peer Group Leader.
PNNI	Private Network-to-Network Interface.
PNNI RCC	PNNI routing control channel. See RCC.
Port	The VSI makes no distinction between trunk ports and end-point ports. "Port" is synonymous with "Interface".
PTSE	PNNI Topology State Element.
PXM	Processor Switch Module.

R
RCC	Routing control channel. A VCC used for the exchange of PNNI routing protocol messages.
RFC	Request For Comment.
Routing Node	In tiered networks terminology, a Routing Node is a larger switch to which one or more Feeders is attached.
rtVBR	Real-time-variable-bit-rate is intended for real-time applications that require tightly constrained delay and delay variation (such as voice and video applications). rtVBR is characterized by PCR, SCR, and MBS.

S
Service Class (aka Service Type, or Service Category)	A concept for grouping connections that share a common set of traffic characteristics and QoS requirements.
Service Class database	The collection of data items which support the Service Class Template concept.
Service Class Template (SCT)	A set of data structures which map ATM Service Types to sets of pre-configured communication parameters.
SCR	Sustainable Cell Rate.
SNMP	Simple Network Management Protocol.
SVC	Switched Virtual Circuit.
SPVC	Soft Permanent Virtual Circuit.

U
UBR	Unspecified Bit Rate is intended for non-real-time application, such as those that do not require tightly constrained delay and delay variation. Traffic in the UBR class is not guaranteed any particular throughput or delay performance. In this regard, UBR is similar to `traditional' IP service.
UNI	User-to-Network Interface.

V
VC	ATM and Frame Relay traffic is carried in Virtual Channels which are set up between adjacent ATM or Frame Relay switches before data transmission occurs. An ATM link between switches may support up to 2²⁸ different VCs, although a small number of VCs is reserved for special purposes.
VCC	Traffic is carried end-to-end on an ATM network on Virtual Channel Connections, which consist of a sequence of Virtual Channels between switches linked by VC cross-connects at the switches.
VCI	Each VC within a specific Virtual Path on a link has a unique Virtual Channel Identifier, which is a 16-bit number (see also VPCI).
VP, VPC, VPI	A Virtual Path is a `bundle' of 2¹⁶ Virtual Connections with the same Virtual Path Identifier, i.e. the first 12 bits of the VPCI. Most ATM switches can switch VPs using only a single cross-connect (instead of up to 2¹⁶). An end-to-end sequence of VPs cross-connected at the intermediate switches is a Virtual Path Connection.
VPCI	Each VC on a link has a unique Virtual Path and Channel Identifier, which is a 28-bit number. The VPCI consists of a 12-bit VPI concatenated with a 16-bit VCI.

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glossary