Specifications

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Cisco MGX 8800/8900 Series Software Configuration Guide

Release 5.1, Part Number OL-6482-01, Rev. A0, January 25, 2005

Chapter 9 Switch Operating Procedures

Managing Bit Error Rate Tests

BERT commands can help you analyze and resolve problems on a physical interface. To conduct a

BERT on a line, a user sends a specified pattern over a line that is configured in loopback mode at the

far end.

The local end receives the loopback pattern, and the user compares the local end pattern to the original

pattern sent from the far end. The number of bit errors discovered in the local (or receive) end pattern

help the user determine the quality of the physical line.

Note BERT is only available for T1 lines and cards that support IMA (PXM1E, PXM45, and MPSM cards).

Configuring a Bit Error Rate Test

Use the following procedure to configure BERT on an MGX switch.

Step 1 Put the appropriate lines into loopback mode.

Step 2 Establish a configuration session with the active PXM1E, PXM45, or MPSM using a user name with

SERVICE_GP privileges or higher.

Note BERT commands are available only on PXM1E, PXM45, and MPSM cards. However, you can

run BERT on any service modules that support T1 lines or IMA.

Step 3 Enter the dspbertcap command to display the loopback and BERT capabilities of a specific line or port

on the current card. The display shows you which test patterns and loopback numbers are available on

the current service module.

dspbertcap <SM Interface> <Test Option>

Table 9-33 describes the dspbertcap command parameters.

Step 4 Enter the cnfbert command as follows to set up BERT parameters on the looped back connection. You

must use the available test patterns and loopback numbers displayed with the dspbertcap command in

Step 3.

Table 9-33 dspbertcap Command Parameters

Parameter Description

SM Interface The format of Service Module Interface is: SMslot.SMLine[.SMport], as follows:

• SMslot can have a value in one of the following ranges: 1-6, 9-14, 17-22, 25-30.

• SMLine has a range from 1 though the maximum number of lines on the card.

• The optional SMport has a value from 1 though the maximum ports supported by

the service module.

Test Option Type one of the following numbers to select the capability to display:

1: BERT capability

2: Loopback capability