Configuration Restrictions

The following restrictions apply to LSQ failure recovery:

• It applies only to Link Services IQ PICs installed in M-series routing platforms, except for M320 routers.
• You must configure the failure-options statement on physical LSQ interfaces, not on MLFR channelized units.
• The Link Services IQ PICs must be associated with SONET link PICs. The paired PICs can be installed on different routers or in the same router; in other words, both interchassis and intrachassis recovery are supported
• Failure recovery is stateless; as a result, route flapping and loss of link state is expected in interchassis recovery, requiring PPP renegotiation. In intrachassis recovery, no impact on traffic is anticipated with Routing Engine failover, but PIC failover results in PPP renegotiation.
• The switchover is not revertive: when the original hardware is restored to service, traffic does not automatically revert back to it.
• Normal APS switchover and PIC-triggered APS switchover can be distinguished only by checking the system log messages.

  Note: When an AS PIC experiences persistent back pressure as a result of high traffic volume for 3 seconds, the condition triggers an automatic core dump and reboot of the PIC to help clear the blockage. A system log message at level LOG_ERR is generated. This mechanism applies to both Layer 2 and Layer 3 service packages.