Installation guide

4-4 Cisco IGX 8400 Series Reference

Universal Switching Module Enhanced

This description of the universal switching module (UXM-E) covers the following topics:

• An introduction includes sections on the UXM-E mode of operation, trunk-mode features,

interface card list, card redundancy, card mismatch, clock sourcing, cellbus bandwidth usage,

conﬁguration for public ATM network service, and conﬁguration for cell trunk-only routes

• Supported trafﬁc and connection types

• Inverse multiplexing over ATM (IMA)

• Activation and conﬁguration of a UXM-E for trunk-mode operation

• Supported trafﬁc and connection types

• Alarms for physical lines and logical (IMA) trunks

• Descriptions of the faceplates on the back cards

The universal switching module (UXM-E) can function in one of two modes. In trunk mode, the

UXM-E supports trunks in the network. In port mode, it as either an ATM User-to-Network Interface

(UNI) or a Network-to-Network interface (NNI). The back cards support multiple ports operating at

OC3/STM1, T3, E3, T1, or E1 rates.

Note The word “port” has two uses in a Cisco WAN switch. “Port mode” refers to the function of

an interface at the edge of a network—the endpoint at which you add connections (UNI) or the

interface between two networks (NNI). Examples of port cards are the UVM, UFM, ALM/A, and

port-mode UXM-E in an IGX switch or an ASI in a BPX switch.

On the other hand, a “port” is also a layer of logical functionality that applies to port cards as well

as trunk cards. For example, whether you activate a line to a router or activate an ATM trunk to the

network, you must subsequently conﬁgure the logical port in either case.

For a UXM-E, therefore, the documentation describes a logical “port” on a port-mode UXM-E for

a UNI or NNI at the edge of a network, yet it also refers to a “port on a UXM-E trunk” as a layer of

logic.

Introduction to the UXM-E Trunk Mode

The UXM-E can transport ATM cells to and from the cellbus at a maximum rate of 310 Mbps in

either direction. The UXM-E can support up to 8000 total connections in trunk mode.

Note The UXM-E in trunk mode cannot support more than 4000 gateway connections. All

remaining connections can be either user or networking connections. For example, if you conﬁgure

2500 gateway connections, you still have 5500 connections available to be used for user or

networking connections.

The UXM-E communicates only ATM cells to either the network or the CPE. On the cellbus,

however, the UXM-E communicates either ATM cells or FastPackets according to the card type.

With another UXM-E, it communicates only in ATM cells. With other cards, the UXM-E

communicates in FastPackets. Through its gateway functionality, the UXM-E translates between

FastPackets and ATM cells so it can transport voice, data, or Frame Relay trafﬁc that other cards have

put in FastPackets.