Specifications

CHAPTER

8-1

Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases

OL-1166-04

Cisco IGX 8400 Series ATM Service

This chapter provides information on provisioning and managing ATM service in a network containing

at least one IGX node. If the network contains other types of nodes, such as a BPX, please refer to the

appropriate product documentation for specific information on provisioning ATM service on those

nodes.

For information about the BPX, see Chapter 1, “The BPX Switch: Functional Overview,” in the

Cisco BPX 8600 Series Installation and Configuration guide.

ATM Service—Functional Overview

The IGX supports the following ATM service features:

• Support for LMI, ELMI, and ILMI local management interface protocols

• ATM standards-based inverse multiplexing (IMA—see the “IMA on the IGX” section on page 5-1)

• Traffic classes and class of service (CoS) templates (or Service Class Template or SCT—see the

“ATM Traffic Classes” section on page 8-1)

• Separately-configurable CoS buffers (Qbins—see the “Qbins” section on page 8-3)

• Qbin templates for use with virtual slave interfaces (VSIs—see the “Qbin Templates” section on

page 8-4)

ATM Traffic Classes

The IGX supports the following standard ATM traffic classes to meet ATM-standard Class of Service

(CoS) requirements:

• Constant bit rate (CBR), used for connections that require precise clocking and undistorted delivery

(such as an uncompressed voice connection or a connection to a streaming video server). CBR

connections have few allowances for burstiness.

• Variable bit rate (VBR), which is divided into two classes—real time (RT) and nonreal time (NRT).

VBR (RT) is used for connections which require a fixed timing relationship between the source and

the destination. VBR (NRT) is used for connections that do not require a fixed timing relationship,

but still need a guaranteed quality of service (QoS). Traffic is permitted to burst within set

limitations.