Users Guide

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
Flow-Based Monitoring Support for ACLs.................................................................................................................. 123
Behavior of Flow-Based Monitoring.......................................................................................................................124
Enabling Flow-Based Monitoring............................................................................................................................125
Conguring UDF ACL.................................................................................................................................................... 126
8 Bidirectional Forwarding Detection (BFD).................................................................................................. 129
How BFD Works............................................................................................................................................................. 129
BFD Packet Format..................................................................................................................................................130
BFD Sessions............................................................................................................................................................. 131
BFD Three-Way Handshake.................................................................................................................................... 132
Session State Changes............................................................................................................................................134
Important Points to Remember.................................................................................................................................... 134
Congure BFD................................................................................................................................................................ 134
Congure BFD for Physical Ports...........................................................................................................................135
Congure BFD for Static Routes............................................................................................................................138
Congure BFD for OSPF.........................................................................................................................................140
Congure BFD for OSPFv3.....................................................................................................................................142
Congure BFD for IS-IS...........................................................................................................................................144
Congure BFD for BGP........................................................................................................................................... 146
Congure BFD for VRRP.........................................................................................................................................153
Conguring Protocol Liveness................................................................................................................................155
Troubleshooting BFD................................................................................................................................................155
9 Border Gateway Protocol IPv4 (BGPv4).....................................................................................................157
Autonomous Systems (AS)........................................................................................................................................... 157
Sessions and Peers........................................................................................................................................................ 159
Establish a Session...................................................................................................................................................159
Route Reectors.............................................................................................................................................................160
BGP Attributes................................................................................................................................................................ 161
Best Path Selection Criteria.....................................................................................................................................161
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