Continue Clause........................................................................................................................................................ 121
IP Fragment Handling..................................................................................................................................................... 121
IP Fragments ACL Examples....................................................................................................................................121
Layer 4 ACL Rules Examples...................................................................................................................................122
Congure a Standard IP ACL........................................................................................................................................ 122
Conguring a Standard IP ACL Filter..................................................................................................................... 123
Congure an Extended IP ACL..................................................................................................................................... 124
Conguring Filters with a Sequence Number....................................................................................................... 124
Conguring Filters Without a Sequence Number.................................................................................................126
Congure Layer 2 and Layer 3 ACLs............................................................................................................................126
Assign an IP ACL to an Interface.................................................................................................................................. 127
Applying an IP ACL......................................................................................................................................................... 127
Counting ACL Hits....................................................................................................................................................128
Congure Ingress ACLs................................................................................................................................................. 128
Congure Egress ACLs..................................................................................................................................................129
Applying Egress Layer 3 ACLs (Control-Plane).................................................................................................... 130
IP Prex Lists.................................................................................................................................................................. 130
Implementation Information..................................................................................................................................... 131
Conguration Task List for Prex Lists...................................................................................................................131
ACL Remarks.................................................................................................................................................................. 134
Conguring a Remark.............................................................................................................................................. 134
Deleting a Remark.................................................................................................................................................... 135
ACL Resequencing......................................................................................................................................................... 136
Resequencing an ACL or Prex List.......................................................................................................................136
Route Maps..................................................................................................................................................................... 137
Implementation Information.....................................................................................................................................137
Logging of ACL Processes............................................................................................................................................ 138
Guidelines for Conguring ACL Logging................................................................................................................139
Conguring ACL Logging.........................................................................................................................................139
Flow-Based Monitoring..................................................................................................................................................140
Behavior of Flow-Based Monitoring.......................................................................................................................140
Enabling Flow-Based Monitoring.............................................................................................................................141
8 Bidirectional Forwarding Detection (BFD).................................................................................................. 143
How BFD Works............................................................................................................................................................. 143
BFD Packet Format..................................................................................................................................................144
BFD Sessions............................................................................................................................................................ 145
BFD Three-Way Handshake.................................................................................................................................... 146
Session State Changes............................................................................................................................................148
Important Points to Remember.................................................................................................................................... 148
Congure BFD................................................................................................................................................................ 149
Congure BFD for Physical Ports...........................................................................................................................149
Congure BFD for Static Routes.............................................................................................................................151
Congure BFD for IPv6 Static Routes...................................................................................................................154
Congure BFD for OSPF.........................................................................................................................................156
Congure BFD for OSPFv3.....................................................................................................................................160
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