Specifications

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Cisco MGX 8850 (PXM45) and MGX 8950 Software Configuration Guide
Release 3, Part Number 78-14788-01 Rev. C0, January 2004
Chapter 7 Switch Operating Procedures
Configuring a Bit Error Rate Test on an AXSM
Configuring a Bit Error Rate Test on an AXSM
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 IMA cards.
Step 1 Put the appropriate lines into loopback mode.
Step 2 Establish a configuration session with the active PXM45 using a user name with SERVICE_GP
privileges or higher.
Note BERT commands are available only on the PXM45 card. However, you can run BERT on any
AXSM card that supports 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>s
Step 4 Enter the cc command to change to the appropriate AXSM card on which you want to run BERT.
Step 5 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.
Unknown.7.PXM.a > cnfbert -ln <bay.line> -tp <testPattern> -tpi <transmit pattern inverse>
-rpi <singleBitErrInsert> -eir <error insertion rate>
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