Administrator Guide

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 IP Mirror Access Group............................................................................................................................ 126
Sample Conguration...............................................................................................................................................127
Example of viewing IP mirror–access–group applied to an Interface................................................................127
7 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............................................................................................................................135
Congure BFD for OSPF.........................................................................................................................................138
Congure BFD for OSPFv3.....................................................................................................................................142
Congure BFD for IS-IS...........................................................................................................................................145
Congure BFD for BGP........................................................................................................................................... 147
Congure BFD for VRRP.........................................................................................................................................153
Conguring Protocol Liveness................................................................................................................................156
Troubleshooting BFD................................................................................................................................................156
8 Border Gateway Protocol IPv4 (BGPv4).................................................................................................... 158
Autonomous Systems (AS)...........................................................................................................................................158
Sessions and Peers........................................................................................................................................................ 160
Establish a Session...................................................................................................................................................160
Route Reectors............................................................................................................................................................. 161
BGP Attributes................................................................................................................................................................162
Best Path Selection Criteria....................................................................................................................................162
Weight........................................................................................................................................................................164
Local Preference.......................................................................................................................................................164
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Contents