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Degraded Fabric Alarms on TX Matrix Plus Router with 3D SIBs


In a routing matrix with a TX Matrix Plus router and 3D SIBs, each FPC (installed on the T1600 or T4000 LCC) contains one or two Packet Forwarding Engines that receive incoming packets from the PICs installed on the FPC and forward them to other FPCs through the switching planes.

The degraded fabric alarm is raised on the source FPC if both the following conditions are met:

  • The active Packet Forwarding Engine destinations are reachable on one or no active switching planes.

  • At least one of the inactive switching planes has a fault that causes the destination Packet Forwarding Engine to become unreachable.

The alarm indicates that the source FPC is running with a degraded fabric condition. This alarm is an early warning of a possible fabric black-hole condition. When the degraded fabric alarm is raised on the source FPC, you can take remedial action to avoid a fabric black-hole condition.

  • By default, the degraded fabric alarm is enabled.

  • The degraded fabric alarm is not raised for the user-initiated events such as:

    • System reboot

    • Destination FPC taken offline

    • LCC taken offline

    • Switch Processor Mezzanine Board restart