Flow-Based Monitoring Support for ACLs.......................................................................................138
Behavior of Flow-Based Monitoring...........................................................................................138
Enabling Flow-Based Monitoring.....................................................................................................140
8 Bidirectional Forwarding Detection (BFD).................................................. 142
How BFD Works................................................................................................................................142
BFD Packet Format......................................................................................................................143
BFD Sessions................................................................................................................................145
BFD Three-Way Handshake........................................................................................................145
Session State Changes................................................................................................................146
Important Points to Remember........................................................................................................147
Configure BFD...................................................................................................................................148
Configure BFD for Physical Ports...............................................................................................148
Enabling BFD Globally.................................................................................................................148
Establishing a Session on Physical Ports....................................................................................149
Changing Physical Port Session Parameters..............................................................................150
Disabling and Re-Enabling BFD..................................................................................................151
Configure BFD for Static Routes.......................................................................................................152
Related Configuration Tasks.......................................................................................................152
Establishing Sessions for Static Routes.......................................................................................152
Changing Static Route Session Parameters...............................................................................153
Disabling BFD for Static Routes..................................................................................................153
Configure BFD for OSPF...................................................................................................................154
Related Configuration Tasks.......................................................................................................154
Establishing Sessions with OSPF Neighbors...............................................................................155
Changing OSPF Session Parameters..........................................................................................156
Disabling BFD for OSPF...............................................................................................................157
Configure BFD for OSPFv3................................................................................................................157
Related Configuration Tasks.......................................................................................................157
Establishing Sessions with OSPFv3 Neighbors...........................................................................157
Changing OSPFv3 Session Parameters......................................................................................158
Disabling BFD for OSPFv3...........................................................................................................158
Configure BFD for BGP.....................................................................................................................159
Prerequisites................................................................................................................................159
Establishing Sessions with BGP Neighbors................................................................................159
Disabling BFD for BGP.................................................................................................................161
Use BFD in a BGP Peer Group....................................................................................................162
Displaying BFD for BGP Information..........................................................................................162
Configure BFD for VRRP...................................................................................................................166
Related Configuration Tasks.......................................................................................................167
Establishing Sessions with All VRRP Neighbors..........................................................................167
Establishing VRRP Sessions on VRRP Neighbors.......................................................................167
7