Users Guide

Congure a Standard IP ACL.........................................................................................................................................110
Conguring a Standard IP ACL Filter.......................................................................................................................111
Congure an Extended IP ACL......................................................................................................................................112
Conguring Filters with a Sequence Number........................................................................................................112
Conguring Filters Without a Sequence Number................................................................................................. 113
Congure Layer 2 and Layer 3 ACLs............................................................................................................................ 114
Assign an IP ACL to an Interface...................................................................................................................................114
Applying an IP ACL..........................................................................................................................................................114
Counting ACL Hits.................................................................................................................................................... 115
Congure Ingress ACLs..................................................................................................................................................115
Congure Egress ACLs...................................................................................................................................................116
Applying Egress Layer 3 ACLs (Control-Plane)..................................................................................................... 117
IP Prex Lists................................................................................................................................................................... 117
Implementation Information..................................................................................................................................... 118
Conguration Task List for Prex Lists...................................................................................................................118
ACL Resequencing..........................................................................................................................................................121
Resequencing an ACL or Prex List.......................................................................................................................122
Route Maps..................................................................................................................................................................... 123
Implementation Information.................................................................................................................................... 123
Logging of ACL Processes............................................................................................................................................ 123
Guidelines for Conguring ACL Logging................................................................................................................124
Conguring ACL Logging.........................................................................................................................................125
Flow-Based Monitoring Support for ACLs..................................................................................................................125
Behavior of Flow-Based Monitoring.......................................................................................................................125
Enabling Flow-Based Monitoring............................................................................................................................ 127
8 Bidirectional Forwarding Detection (BFD).................................................................................................. 128
How BFD Works............................................................................................................................................................. 128
BFD Packet Format..................................................................................................................................................129
BFD Sessions............................................................................................................................................................ 130
BFD Three-Way Handshake.....................................................................................................................................131
Session State Changes............................................................................................................................................133
Important Points to Remember.................................................................................................................................... 133
Congure BFD................................................................................................................................................................ 133
Congure BFD for Physical Ports...........................................................................................................................134
Congure BFD for Static Routes............................................................................................................................ 137
Congure BFD for OSPF.........................................................................................................................................139
Congure BFD for OSPFv3.....................................................................................................................................142
Congure BFD for IS-IS...........................................................................................................................................143
Congure BFD for BGP........................................................................................................................................... 145
Congure BFD for VRRP.........................................................................................................................................152
Conguring Protocol Liveness................................................................................................................................ 154
Troubleshooting BFD................................................................................................................................................154
9 Border Gateway Protocol IPv4 (BGPv4).................................................................................................... 156
Autonomous Systems (AS)...........................................................................................................................................156
Sessions and Peers........................................................................................................................................................ 158
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