Cisco IGX 8400 Series Switches

Document ID: 20374

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
Configure
      Interworking Criteria
      SIW Types and Supported Connections
      Configuration Examples
Verify
Troubleshoot
NetPro Discussions
Related Information

Introduction

This document provides configuration examples of ATM to Frame Relay Service Interworking (SIW) between IGX, BPX, MGX 8220 and Cisco routers. It has examples for both SIW modes specified in the standards: translational and transparent. Although SIW is supported on the MGX 8250, 8230, and 8850 platforms, it is not covered in this document. The connection types illustrated provide information on the basic techniques and how to apply those techniques in situations not covered by this document.

ATM to Frame Relay SIW offers connectivity between two end points where one end point is a Frame Relay service user and the other end is an ATM service user. The ATM service user does not perform any Frame Relay service-specific functions, and the Frame Relay service user performs no ATM service-specific functions. All mapping functions are performed by the intermediate interworking function (IWF) device. The basic function of the IWF is to have two stacks of protocols (one for each side), and be able to make mapping to as may functions as possible.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

• Cisco IGX 8400 hardware platforms

• Cisco BPX 8600 hardware platforms

• Cisco MGX 8220 hardware platform

• All Cisco router hardware platforms that support Frame Relay and ATM encapsulations

• Cisco WAN switch software version 9.1.x, and later

• Cisco IOS^® Software 12.0, or later

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Configure

This section describes SIW configuration criteria, types, supported connections, and configuration examples.

Interworking Criteria

Due to the poor acceptance of switched virtual circuits (SVCs) in the Frame Relay world, the actual implementations of interworking consist mainly of permanent virtual circuits (PVCs). These criteria apply to all ATM to Frame Relay (ATF) connections on Cisco BPX and IGX platforms:

• Supported connections:

  • ATF connections between any combination of ATM and Frame Relay UNI and NNI ports

  • Virtual circuit connections

• Unsupported connections:

  • Virtual path connections

  • ATF bundled connections and ATF point-to-point (frame forwarding) connections

• ATF connections can be mastered by the IGX switch or BPX switch end.

• ATF connections use the Frame Relay trunk queues: bursty data A for non-ForeSight, bursty data B for ForeSight.

• Bandwidth related parameters are defined by cells per second (cps) on the BPX switch and bits per second (bps) on the IGX switch. On a given endpoint node, the bandwidth parameters for both ends of the ATF connection are changed or displayed using this end's units. This does not require you to convert from cps to bps repeatedly.

• ATF with ForeSight connections use the ABR egress queue.

SIW Types and Supported Connections

SIW offers two types of connections called translation mode and transparent mode, selected for each PVC during configuration.

In translation mode (SIW-X), the translation is between two protocol encapsulation methods specified by IETF (RFC 1490/RFC 1483). The IWF maps between the two encapsulations due to the incompatibilities of the two methods.

Transparent mode (SIW-T) simply offers the transport of the payload. The IWF forwards the encapsulations unaltered and no mapping is performed.

For more information on SIW modes and mapping functions, refer to Configuring Frame Relay to ATM Network and Service Interworking and MGX 8220 Service Modules.

The IWF for Frame Relay to ATM SIW is implemented on the FRSM card in all MGX platforms, and the UFM on IGX. The FRM on IGX does not support SIW. This table lists the modules that support SIW connections on the BPX or IGX and MGX 8220 platforms:

Configuration Examples

For a configuration example for routing nodes only, refer to ATM to Frame-Relay Service Interworking Connection Examples for a Flat Network.

For a configuration example for interface shelves or feeders connected to routing nodes, refer to Configuring ATM-Frame Relay Service Interworking.

Verify

There is currently no verification procedure available for this configuration.

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

NetPro Discussions

Related Information

• Configuring Frame Relay to ATM Network and Service Interworking
• Troubleshooting PVC Problems
• When Should Scrambling Be Enabled on ATM Virtual Circuits?
• Command Reference, Release 9.3.30
• IGX 8400 Series Switches - Support Page
• Cisco WAN Switching Solutions - Cisco Documentation
• Guide to New Names and Colors for WAN Switching Products
• Technical Support - Cisco Systems