Cisco nonstop forwarding (NSF) continues forwarding packets while routing protocols converge, therefore
avoiding a route flap on switchover. When an RP failover occurs, the Forwarding Information Base (FIB)
marks installed paths as stale by setting a new epoch. Subsequently, the routing protocols reconverge and
populate the RIB and FIB. Once all NSF routing protocols converge, any stale routes held in the FIB are
removed. A failsafe timer is required to delete stale routes, in case of routing protocol failure to repopulate
the RIB and FIB.
RIP registers as an IPv6 NSF client. Doing so has the benefit of using RIP routes installed in the Cisco
Express Forwarding table until RIP has converged on the standby.
avoiding a route flap on switchover. When an RP failover occurs, the Forwarding Information Base (FIB)
marks installed paths as stale by setting a new epoch. Subsequently, the routing protocols reconverge and
populate the RIB and FIB. Once all NSF routing protocols converge, any stale routes held in the FIB are
removed. A failsafe timer is required to delete stale routes, in case of routing protocol failure to repopulate
the RIB and FIB.
RIP registers as an IPv6 NSF client. Doing so has the benefit of using RIP routes installed in the Cisco
Express Forwarding table until RIP has converged on the standby.
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