IP Fragment Handling............................................................................................................................................ 115
IP Fragments ACL Examples........................................................................................................................... 116
Layer 4 ACL Rules Examples...........................................................................................................................116
Configure a Standard IP ACL................................................................................................................................ 117
Configuring a Standard IP ACL Filter............................................................................................................ 118
Configure an Extended IP ACL.............................................................................................................................119
Configuring Filters with a Sequence Number.............................................................................................119
Configuring Filters Without a Sequence Number..................................................................................... 120
Configure Layer 2 and Layer 3 ACLs...................................................................................................................121
Assign an IP ACL to an Interface..........................................................................................................................121
Applying an IP ACL..................................................................................................................................................121
Counting ACL Hits............................................................................................................................................ 122
Configure Ingress ACLs.........................................................................................................................................122
Configure Egress ACLs.......................................................................................................................................... 123
Applying Egress Layer 3 ACLs (Control-Plane)...........................................................................................124
IP Prefix Lists............................................................................................................................................................124
Implementation Information..........................................................................................................................125
Configuration Task List for Prefix Lists......................................................................................................... 125
ACL Resequencing................................................................................................................................................. 128
Resequencing an ACL or Prefix List..............................................................................................................129
Route Maps..............................................................................................................................................................130
Implementation Information..........................................................................................................................130
Logging of ACL Processes....................................................................................................................................130
Guidelines for Configuring ACL Logging..................................................................................................... 131
Configuring ACL Logging................................................................................................................................132
Flow-Based Monitoring Support for ACLs........................................................................................................ 132
Behavior of Flow-Based Monitoring.............................................................................................................133
Enabling Flow-Based Monitoring..................................................................................................................134
Configuring UDF ACL............................................................................................................................................ 135
8 Bidirectional Forwarding Detection (BFD)..................................................................................................... 138
How BFD Works......................................................................................................................................................138
BFD Packet Format...........................................................................................................................................139
BFD Sessions..................................................................................................................................................... 140
BFD Three-Way Handshake............................................................................................................................141
Session State Changes.....................................................................................................................................143
Important Points to Remember.......................................................................................................................... 143
Configure BFD.........................................................................................................................................................143
Configure BFD for Physical Ports..................................................................................................................144
Configure BFD for Static Routes....................................................................................................................147
Configure BFD for OSPF................................................................................................................................. 149
Configure BFD for OSPFv3............................................................................................................................. 152
Configure BFD for IS-IS...................................................................................................................................153
Configure BFD for BGP....................................................................................................................................155
Configure BFD for VRRP................................................................................................................................. 162
Configuring Protocol Liveness...................................................................................................................... 164
Troubleshooting BFD.......................................................................................................................................164
9.10(0.1)
6