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
Configuring a Line Loopback
Record: 1791 ActvComdID: 0 StdbyComID: 7
=============================================================
dbInd: 1 - dbName: sm_mib_v21
tblInd: 5 - tblName: mib29
Record: 1792 ActvComdID: 0 StdbyComID: 7
=============================================================
Note The disk verification utility only logs discrepancies. It does not synchronize the differences.
Troubleshooting Active and Standby Card Disk Discrepancies
If discrepancies are found by the disk verification utility, follow these steps:
Step 1 Locate the logs that pertain to the affected database(s) for the indicated slot.
Step 2 If possible, perform application specific task to resync that DB record. For example, remove and
re-install, and re-provision the card.
Step 3 If you can not perform application specific tasks on the card, enter the resetcd command to reset the
standby PXM to re-synchronize the database.
If you provision connections while the verifydiskdb check command is running, discrepancies will be
flagged, even if the information between the active PXM and the standby PXM is synchronized. To
ensure an accurate log of discrepancies, wait for the verifydiskdb check to finish running before you
provision connections.
Configuring a Line Loopback
If a connection fails and you do not know which end of the connection is causing the problem, putting a
line into loopback mode can help you determine what the problem is and where it occurs on a connection.
In an MGX 8830, an MGX 8850, or an MGX 8880, loopback lines provide CLI-based line level
monitoring capabilities.
When a line is put into loopback, the receiving switch takes all of the data it receives and returns it
unchanged back to the sender. The physical line in a loopback configuration is connected between a CPE
and a switch; one physical line is connected from the tx (Transmit port) of the CPE to the rx (receive)
port of a card on the switch you are testing. Another physical line is connected between the tx port of
the same card and the receive port of the CPE.
Configuring Loopback Line Tests on PXM1E, AXSM, and MPSM Cards
Once the physical connection is established, you need to use the CLI to put the connection into loopback
mode.
The following types of loopback are supported on PXM1E, AXSM, and MPSM cards:
• Far-end line loopback - Loopback appears at the far-end of the CPE when you send a loopback
activation code from the card. The CPE enters a loop mode in which it returns the received data back
to the card. The CPE continues to return the data back until it receives a no-loopback request.This
kind of loopback can be used to run tests, such as BERT.