[Problem Description]
Trigger condition:
1. A revertive tunnel and static SNCTP receive/transmit lower order services in back-to-back mode.
2. The revertive tunnel is rerouted, or optimized after a rerouting.
Symptom:
The tunnel cannot be reverted to the original trail, or tunnel optimization fails. CP_LSP_SIG_EXCEPT and CP_SER_NOT_OR alarms are reported, respectively indicating that the ASON signaling is abnormal and the service is not on the original trail.
The two alarms are not supported in earlier versions.
Identification method:
This issue can be identified when the following three conditions are met:
1. The revertive tunnel and static SNCTP receive/transmit lower order services in back-to-back mode.
3. The tunnel is rerouted, and then reverted to the original trail or optimized.
4. The function of 1+1 linear MSP lower order broadcast optimization is disabled.
[Root Cause]
After the tunnel is rerouted, only part of the cross-connection information at the algorithm layer of the NE software is updated. If the tunnel is reverted to the original trail or optimized, the newly generated services conflict with the cross-connection information that is not updated. As a result, the tunnel reversion or optimization fails.
[Impact and Risk]
The revertive tunnel cannot be reverted to the original trail, or the tunnel optimization fails.
[Measures and Solutions]
Recovery measures:
Enable the 1+1 linear MSP lower order broadcast optimization function, and manually trigger a full calculation. After the tunnel service is reverted to the original trail and the CP_LSP_SIG_EXCEPT alarm is cleared, disable the 1+1 linear MSP lower order broadcast optimization function.
Preventive measures:
Do not configure the static SNCTP and tunnel in back-to-back mode.
Solution:
Upgrade an NE to one of the following versions:
l If the NE version is one of V100R006, V100R007, or V100R008 versions earlier than V100R008C02SPC500, upgrade the NE to V100R008C02SPC500 or a later V100R008 version.
l If the NE version is one of V100R009 or V100R010 versions earlier than V100R010C03SPC200, upgrade the NE to V100R010C03SPC200 or a later version.
For V100R010C03SPC200 or a later version, the SNCTP protection cannot be configured for VC-4 services. Rectification needs to be made to an NE whose VC-4 services are configured with SNCTP protection before an upgrade.
Material handling after replacement:
N/A
[Inspection Tool Applicable or Not]
N/A
[Rectification Scope and Time Requirements]
N/A
[Rectification Instructions]
N/A
[Attachment]
N/A
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