Setup Guide

Congure Layer 2 and Layer 3 ACLs............................................................................................................................ 121
Assign an IP ACL to an Interface..................................................................................................................................122
Applying an IP ACL.........................................................................................................................................................122
Counting ACL Hits....................................................................................................................................................123
Congure Ingress ACLs................................................................................................................................................. 123
Congure Egress ACLs.................................................................................................................................................. 124
Applying Egress Layer 3 ACLs (Control-Plane).................................................................................................... 125
IP Prex Lists.................................................................................................................................................................. 125
Implementation Information.................................................................................................................................... 126
Conguration Task List for Prex Lists.................................................................................................................. 126
ACL Remarks.................................................................................................................................................................. 129
Conguring a Remark.............................................................................................................................................. 129
Deleting a Remark.................................................................................................................................................... 130
ACL Resequencing..........................................................................................................................................................131
Resequencing an ACL or Prex List........................................................................................................................131
Route Maps.....................................................................................................................................................................132
Implementation Information.................................................................................................................................... 132
Flow-Based Monitoring..................................................................................................................................................133
Behavior of Flow-Based Monitoring.......................................................................................................................133
Enabling Flow-Based Monitoring............................................................................................................................134
Conguring IP Mirror Access Group............................................................................................................................ 135
Sample Conguration...............................................................................................................................................136
Example of viewing IP mirror–access–group applied to an Interface................................................................137
7 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................................................................................................................................................................ 144
Congure BFD for Physical Ports...........................................................................................................................144
Congure BFD for Static Routes............................................................................................................................146
Congure BFD for IPv6 Static Routes...................................................................................................................149
Congure BFD for OSPF.........................................................................................................................................152
Congure BFD for OSPFv3.....................................................................................................................................156
Congure BFD for IS-IS...........................................................................................................................................159
Congure BFD for BGP............................................................................................................................................161
Congure BFD for VRRP.........................................................................................................................................169
Conguring Protocol Liveness.................................................................................................................................171
8 Border Gateway Protocol (BGP).................................................................................................................172
BGP IP version 4 (BGPv4) Overview.......................................................................................................................... 172
BGP Autonomous Systems..................................................................................................................................... 172
AS4 Number Representation...................................................................................................................................174
6
Contents