Below topology was used for this post, and all the configuration happened on two Cisco CSR1000v
BGP Nonstop Forwarding
- During normal NSF operation, CEF on the active RP synchronizes its current FIB and adjacency databases with the FIB and adjacency databases on the standby RP
- While switching over, the traffic is depended on CEF, once the routing protocol is converged, FIB will be updated
- RIB repopulating happens prefix-by-prefix, thus the same for FIB and adjacency table
- For BGP NSF, graceful-restart needs to be configured on both ends of a BGP session. Although one end could be only NSF-aware (not SSO capable)
- BFD can’t be enabled simultaneously with NSF for BGP
- SSO is not integrated into EIGRP, hence only NSF awareness is supported