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Congure a Route Map for Route Tagging............................................................................................................ 116
Continue Clause........................................................................................................................................................ 116
IP Fragment Handling..................................................................................................................................................... 117
IP Fragments ACL Examples....................................................................................................................................117
Layer 4 ACL Rules Examples....................................................................................................................................117
Congure a Standard IP ACL.........................................................................................................................................118
Conguring a Standard IP ACL Filter......................................................................................................................119
Congure an Extended IP ACL.....................................................................................................................................120
Conguring Filters with a Sequence Number.......................................................................................................120
Conguring Filters Without a Sequence Number.................................................................................................123
Congure Layer 2 and Layer 3 ACLs............................................................................................................................124
Assign an IP ACL to an Interface..................................................................................................................................124
Applying an IP ACL.........................................................................................................................................................124
Counting ACL Hits....................................................................................................................................................125
Congure Ingress ACLs................................................................................................................................................. 125
Congure Egress ACLs.................................................................................................................................................. 126
Applying Egress Layer 3 ACLs (Control-Plane).....................................................................................................127
IP Prex Lists...................................................................................................................................................................127
Implementation Information.................................................................................................................................... 128
Conguration Task List for Prex Lists.................................................................................................................. 128
ACL Resequencing..........................................................................................................................................................131
Resequencing an ACL or Prex List.......................................................................................................................132
Route Maps.....................................................................................................................................................................133
Implementation Information.................................................................................................................................... 133
Conguring UDF ACL.....................................................................................................................................................133
Conguring IP Mirror Access Group............................................................................................................................ 136
Sample Conguration...............................................................................................................................................137
Example of viewing IP mirror–access–group applied to an Interface................................................................137
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
Congure BFD................................................................................................................................................................ 143
Congure BFD for Physical Ports...........................................................................................................................144
Congure BFD for Static Routes............................................................................................................................146
Congure BFD for OSPF.........................................................................................................................................148
Congure BFD for OSPFv3.....................................................................................................................................152
Congure BFD for IS-IS...........................................................................................................................................155
Congure BFD for BGP........................................................................................................................................... 157
Congure BFD for VRRP.........................................................................................................................................165
Conguring Protocol Liveness................................................................................................................................ 167
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