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Avaya CM cmgDs1Layer2Down on DS1

Jeremy Boilard

Problem Statement

Avaya Communication Manager reports a Minor cmgDs1Layer2Down alarm indicating ISDN Layer 2 is down on a DS1. Diagnostics may show failures on the MG-DS1 board and associated ISDN trunk signaling.

Impact

The affected DS1/PRI may be out of service, and associated ISDN signaling or trunking may fail. If the circuit is still in production, inbound or outbound calls using that trunk group may be impacted. If the DS1 board and trunks were decommissioned, the alarm may be expected and require documentation or monitoring cleanup rather than repair.

Alarm

cmgDs1Layer2Down - ISDN Layer-2 is down on a Ds1

Troubleshooting Steps

  1. Identify the affected DS1 maintenance object, board, and any associated ISDN trunk or trunk group from the alarm details and Communication Manager inventory. Use generic placeholders when documenting the circuit, such as <ds1-board> and <isdn-trunk-port>.
  2. Run board diagnostics on the affected DS1 board using: test board <ds1-board> long clear.
  3. Review MG-DS1 test results. In the observed case, Test #139 failed and Test #50 aborted with error code 1412, while other board tests passed.
  4. Run diagnostics for the associated ISDN trunk or related board/port using the appropriate Communication Manager test command, such as: test board <associated-board> long clear, or the applicable trunk test command for the environment.
  5. Review ISDN-TRK results. In the observed case, Test #255 failed with error code 4 on the associated ISDN trunk.
  6. Correlate the DS1 and ISDN trunk failures to confirm whether the issue is an active Layer-2 outage affecting the circuit and signaling path.
  7. Check operational awareness, change records, circuit inventory, and monitoring scope to determine whether the DS1 board, circuit, or trunks were intentionally decommissioned.
  8. If the circuit is expected to be active, escalate to the appropriate voice/network support team or carrier/vendor for DS1/PRI Layer-2 restoration and continue testing after remediation.
  9. If the board and trunks are confirmed decommissioned, document the expected condition and update monitoring, inventory, or stale configuration through the normal change process to prevent repeat alarms.

Resolution

In the documented case, diagnostics confirmed DS1 Layer-2 and associated ISDN trunk failures, but the affected board and trunks were later confirmed to be decommissioned. No circuit repair was required after decommissioning awareness was confirmed; the condition should be documented for future reference and handled through monitoring or inventory cleanup as appropriate.