Description of the problem

MPLS_PW_MISMERGE alarm is reported on PTN950/960 devices at XX locations.

Processing

The MPLS_PW_MISMERGE alarm indicates that the OAM receiver has received both expected correct messages and unintended OAM messages during the cycle, and unintended means that the LSRID or PWID is incorrect.

1. Analyze the alarm and find that the alarm is repeatedly reported.

2. Query the PW configuration and determine that the LSRID of the opposite end is 1.11.2.161.

3, capture the OAM message to analyze the message, and found that there is an unintended message received from the LSRID 1.11.2.25 PTN3900, and the ID is 1958.

4. Examine the LSRID 1.11.2.25 network element and find that there is no PW with ID 1958, but there is a Tunnel ID 1958 and OAM is enabled.

5. Further confirm that the Tunnel is a discrete Tunnel, confirm that the working channel involved in the discrete Tunnel is no longer carrying VPN services, delete the corresponding TunnelAPS, clear the OAM configuration of the discrete Tunnel, and the MPLS_PW_MISMERGE alarm disappears.

FAQ: Why is Tunnel 1958 discrete?

Because in the process of replacing PTN950 with PTN960 in the current network, only PW and VPN services are cleaned up after the 950 equipment is replaced, but not discrete Tunnel. it is recommended to clean up the discrete services such as VPN, PW, Tunnel, etc., after the equipment is replaced in the future.

Root cause

There were discrete Tunnel OAM messages sent to the PWOAM, which resulted in the receiver receiving both expected and unanticipated OAM messages, leading to the reporting of MISMERGE alarms.

Solution

Clean up unused discrete Tunnel and remove its OAM.

Recommendations and Summary

It is recommended that the existing network clean up the garbage services (discrete services, PWs, and Tunnel) in a timely manner after equipment relocation, replacement, cutover expansion, and other operations to maintain the purity and security and robustness of the network.

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