After there was a fiber cut, customer reported an OptiX OSN 3500 host version 188.8.131.52 which interrupted the service configured in slot 6 SSN1EGS401 board in
VCTRUNK1. Customer confirmed that the service was configured in an MSP(Multiplex Section Protection) 1+1 protection. After the fiber was recovered, the services were recovered too, but
customer wants to avoid this problem to happen again. The service is configured as a Trunk Link.
1. Verify the services that are configured the Trunk Link Management
2. Verify the service configured in the SDH Trail Management
3. Verify the Port attributes for each N1EGS4 end.
Configuration > Ethernet Interface Management > Ethernet Interface > Internal Port > LCAS Tab.
Then, we verified that LCAS function was not enable in this port.
Trunk Link Management showed that there were two routes for different virtual containers. In this case the VCTRUNK maps 4xVC12 virtual concatenations, then
the bandwidth of the services is total 8 Mpbs. When one channel of VC12-4v fails, the LCAS suppress the failed channel and adjusts the capacity of the VCTRUNK. During the fiber cut, the bit rate of the services would have decreased
instead of interrupted completely. Using the LCAS function the system would have report an alarms and the loss of partial bandwidth but the service of the entire
VCTRUNK would have not been interrupted.
The LCAS function can be used to dynamical adjust the bandwidth AND protect virtual concatenation, whereby making the network more robust and flexible.