The bold line shows that IS-IS BFD sessions are enabled.R2(conf-router_isis)#bfd all-neighborsR2(conf-router_isis)#do show bfd neighbors* - Active session roleAd Dn - Admin DownC - CLII - ISISO - OSPFR - Static Route (RTM)LocalAddr RemoteAddr Interface State Rx-int Tx-int Mult Clients* 2.2.2.2 2.2.2.1 Te 2/1 Up 100 100 3 IChanging IS-IS Session ParametersBFD sessions are configured with default intervals and a default role.The parameters that you can configure are: Desired TX Interval, Required Min RX Interval, Detection Multiplier, and system role. Theseparameters are configured for all IS-IS sessions or all IS-IS sessions out of an interface. If you change a parameter globally, the changeaffects all IS-IS neighbors sessions. If you change a parameter at the interface level, the change affects all IS-IS sessions on that interface.To change parameters for all IS-IS sessions or for IS-IS sessions on a single interface, use the following commands.To view session parameters, use the show bfd neighbors detail command, as shown in Verifying BFD Sessions with BGPNeighbors Using the show bfd neighbors Command in Displaying BFD for BGP Information.• Change parameters for all IS-IS sessions.ROUTER-ISIS modebfd all-neighbors interval milliseconds min_rx milliseconds multiplier value role [active |passive]• Change parameters for IS-IS sessions on a single interface.INTERFACE modeisis bfd all-neighbors interval milliseconds min_rx milliseconds multiplier value role [active| passive]Disabling BFD for IS-ISIf you disable BFD globally, all sessions are torn down and sessions on the remote system are placed in a Down state.If you disable BFD on an interface, sessions on the interface are torn down and sessions on the remote system are placed in a Down state.Disabling BFD does not trigger a change in BFD clients; a final Admin Down packet is sent before the session is terminated.To disable BFD sessions, use the following commands.• Disable BFD sessions with all IS-IS neighbors.ROUTER-ISIS modeno bfd all-neighbors• Disable BFD sessions with IS-IS neighbors on a single interface.INTERFACE moseisis bfd all-neighbors disable164 Bidirectional Forwarding Detection (BFD)
