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Nortel CS1000 ELAN009 Alarm

Jeremy Boilard

Problem Statement

A Nortel CS1000 (CS1K) reports a Minor ELAN009 ACT alarm indicating that an ELAN host IP is disabled because a write to socket failed due to a far-end disconnect, network interface problem, or Ethernet problem.

Impact

The affected ELAN link or host communication path may be unavailable or unstable. Management, signaling, or related ELAN-dependent connectivity may be impacted until the far-end connection or network interface recovers.

Alarm

ELAN009 ACT - ELAN host IP disabled; write to socket failed due to far-end disconnect or network interface/Ethernet problems.

Troubleshooting Steps

  1. Confirm the active alarm details in the monitoring dashboard, including device type, maintenance object, alarm code, affected ELAN link, and host IP reference.
  2. Check whether a corresponding recovery or enable message is present, such as ELAN014 indicating the ELAN host IP is enabled.
  3. Verify network reachability between the CS1000 and the far-end ELAN host using standard connectivity checks such as ping or traceroute from an appropriate management point.
  4. Inspect the Ethernet path for the affected ELAN connection, including switch port status, interface errors, cabling, VLAN assignment, and recent link flaps.
  5. Confirm the far-end device or service is powered on, reachable, and not administratively disabled.
  6. Review recent network or device changes that could have interrupted the socket connection, including firewall, routing, VLAN, or interface configuration changes.
  7. If connectivity has recovered, monitor the alarm dashboard to confirm the ELAN009 alarm clears and does not recur.
  8. If the alarm remains active after network reachability and far-end status are confirmed, escalate to the Nortel CS1000 support team with the alarm text, affected ELAN link, timestamps, and relevant network test results.

Resolution

The alarm condition is resolved when the ELAN host communication is restored and the system reports the ELAN host IP as enabled, commonly indicated by an ELAN014 enable message. Continue monitoring to confirm the ELAN009 alarm remains cleared.