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Avaya cmgSyncSignalFault

Jeremy Boilard

Problem Statement

Avaya Communication Manager (Core) reports a Major cmgSyncSignalFault alarm with alarm code ACT. The alarm indicates that the synchronization signal was lost for the provisioned clock-sync source on an E1/T1 media module or MM710 media module.

Impact

Loss of the configured external synchronization source can cause the media gateway to fall back to its internal clock. If unresolved, this may lead to timing slips, trunk errors, degraded voice quality, or service instability on affected E1/T1 spans.

Alarm

cmgSyncSignalFault - Synchronization signal lost; Alarm Code: ACT; Severity: Major

Troubleshooting Steps

  1. Access the Media Gateway Processor (MGP) CLI for the affected media gateway.
  2. Run `show sync timing` to verify the configured synchronization source, active source, and whether the provisioned clock-sync source has a good signal.
  3. Confirm that the E1/T1 media module or MM710 media module is correctly administered on Avaya Communication Manager. If it has not been added, use the System Access Terminal (SAT) to run the appropriate `add DS1` administration before attempting MGP CLI synchronization commands.
  4. From the MGP CLI, configure the primary and secondary clock sources for the E1/T1 span using the `set sync interface` command. Do not configure the internal clock as a CLI source; the local/internal clock is built in and is not administrable as a primary or secondary external source.
  5. From the MGP CLI, run `set sync source` to select the specific MM710 E1/T1 media module to be used as the active clock reference.
  6. Run `show sync timing` again to confirm that the intended source is provisioned and active.
  7. If physical access is available, verify the yellow LED behavior on the MM710 media module. Yellow LED on for approximately 2.7 seconds and off for 0.3 seconds indicates active mode using an external synchronization reference. Yellow LED on for approximately 0.3 seconds and off for 2.7 seconds indicates active mode using the internal onboard clock, meaning external sync timing was not successfully applied.
  8. If the alarm remains active after configuration is verified, check the external timing source, E1/T1 span health, cabling, carrier handoff, and any upstream clock provider issues before escalating to the appropriate voice or carrier support team.

Resolution

Restore or correctly configure the external synchronization reference for the affected E1/T1 or MM710 media module. After setting the primary/secondary sync interface and active sync source, verify with `show sync timing` that the external source is active and confirm that the cmgSyncSignalFault alarm clears.