You can use soft reconfiguration to enable the nondisruptive reapplication of inbound policies. Issuing the command causes the router to store copies of the routes received from the specified peer or from all members of the specified peer group. The route copies are stored unmodified, before application of inbound policies.
If you then change your inbound policies, you can apply them to the stored routes without clearing your BGP sessions—and causing network disruptions—by issuing the clear ip bgp soft in command.
neighbor soft-reconfiguration inbound
- host1(config)#router bgp 37
- host1(config-router)#neighbor 192.168.1.1 remote-as 42
- host1(config-router)#neighbor 192.168.1.1 soft-reconfiguration inbound
If the route-refresh capability was not negotiated with the peer, BGP automatically bounces the session. The Adj-RIBs-In table is repopulated when routes are received from the peer after the session comes back up.