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MG-DS1 Alarm Troubleshooting

Jeremy Boilard

Problem Statement

The MG-DS1 alarm indicates a DS1 Interface Media Module alarm in Avaya Communication Manager. This alarm can be raised for multiple reasons, including DS1 physical connectivity, far-end service state, protocol mismatch, excessive bit errors, or synchronization issues. Related ISDN-PRI signaling issues may also appear when the D-channel or associated signaling group is out of service.

Impact

A DS1 or ISDN-PRI service issue can affect trunk availability and call processing. If the D-channel is down, the associated trunk group is usually down as well.

Alarm

MG-DS1

Troubleshooting Steps

  1. Check Avaya Communication Manager for active alarms and confirm whether MG-DS1 is still present.
  2. If an ISDN-PRI signaling issue is suspected, run `status signaling-group` for the administered signaling group ID and verify whether it is in service.
  3. If the signaling group is out of service, run `list signaling-group` to identify the associated DS1 or C-LAN resource.
  4. Run `test board` against the associated DS1 or C-LAN circuit pack.
  5. For DS1 test results: if test 138 fails, investigate loss of physical connectivity.
  6. For DS1 test results: if test 139 fails, the remote end is typically out of service. Engage the service provider or support team responsible for the far-end equipment.
  7. For DS1 test results: if test 140 fails, check for a protocol mismatch between the local and far end. Try changing the CRC setting and retest. If the test still fails, restore the original CRC setting.
  8. For DS1 test results: if test 142 fails, investigate the physical line because the bit error rate is greater than 1/1000.
  9. For DS1 test results: if test 144 fails, check for DS1 signal slips. Run `status synchronization` and verify the synchronization setting for the Media Gateway or Port Network. A stable synchronization source is required.
  10. For C-LAN test results: if the ETH-PT test fails, investigate the Ethernet switch connection.
  11. If C-LAN tests pass, troubleshoot connectivity from the C-LAN to the far-end node. Use `list signaling-group` to identify far-end node details.
  12. Refer to the applicable Avaya Communication Manager alarms, events, and logs documentation for complete MG-DS1 alarm cause and repair information for the deployed release.

Resolution

Clear the underlying DS1, ISDN-PRI signaling, physical line, far-end, protocol, Ethernet, or synchronization issue identified by testing. After corrective action, verify that the signaling group and trunk resources return to service and confirm there are no active Communication Manager alarms.