Problem Statement
Avaya Communication Manager generated a minor cmgDs1Layer2Down alarm indicating ISDN Layer 2 was down on a DS1. In some occurrences the alarm cleared automatically, while a longer outage required carrier/local LEC investigation.
Impact
The affected DS1/PRI trunk was unavailable or unstable while Layer 2 was down, potentially impacting inbound and outbound calls routed over that circuit.
Alarm
cmgDs1Layer2Down / ACT: ISDN Layer-2 is down on a Ds1.
Troubleshooting Steps
- Confirm the alarm is active in the monitoring dashboard and record the affected DS1 equipment identifier or port reference without relying only on the alarm summary.
- Check whether the alarm clears on its own after a short interval; some occurrences cleared automatically within minutes or hours.
- If the alarm remains active, open a carrier ticket for the affected DS1/PRI and request circuit testing.
- Ask the carrier or local LEC to test directly from the demarc, especially if they initially report the circuit is clean from the network side.
- Coordinate site access if the carrier needs to dispatch to the demarc or cross-connect location.
- If the carrier certifies the circuit clean to the demarc and the alarm remains active, consider an onsite field engineer dispatch to inspect the DS1 handoff, cabling, smart jack/demarc, and PBX-side DS1 interface.
- Avoid replacing Avaya DS1 hardware until carrier demarc and cross-connect issues have been ruled out.
- After carrier or onsite work, verify the DS1 returns to service, the alarm clears, and the circuit remains error-free.
Resolution
The most supported resolution path was carrier/local LEC investigation at the demarc and cross-connect. In the documented longer outage, the carrier found and corrected a cross-connect issue, after which the DS1 came back up and ran error-free. Other occurrences cleared automatically with no additional corrective action documented, so transient carrier or circuit-layer events should be monitored but escalated if they persist or recur.