Users Guide

Applying an IP ACL..........................................................................................................................................................113
Counting ACL Hits.................................................................................................................................................... 113
Configure Ingress ACLs..................................................................................................................................................113
Configure Egress ACLs.................................................................................................................................................. 114
Applying Egress Layer 3 ACLs (Control-Plane).................................................................................................... 115
IP Prefix Lists...................................................................................................................................................................115
Implementation Information.....................................................................................................................................116
Configuration Task List for Prefix Lists..................................................................................................................116
ACL Resequencing..........................................................................................................................................................119
Resequencing an ACL or Prefix List...................................................................................................................... 120
Route Maps......................................................................................................................................................................121
Implementation Information.....................................................................................................................................121
Flow-Based Monitoring Support for ACLs..................................................................................................................122
Behavior of Flow-Based Monitoring...................................................................................................................... 122
Enabling Flow-Based Monitoring............................................................................................................................123
Configuring IP Mirror Access Group............................................................................................................................124
Sample Configuration.............................................................................................................................................. 125
Example of viewing IP mirror–access–group applied to an Interface...............................................................125
7 Bidirectional Forwarding Detection (BFD)..................................................................................................126
How BFD Works.............................................................................................................................................................126
BFD Packet Format..................................................................................................................................................127
BFD Sessions............................................................................................................................................................ 128
BFD Three-Way Handshake................................................................................................................................... 129
Session State Changes.............................................................................................................................................131
Important Points to Remember.....................................................................................................................................131
Configure BFD.................................................................................................................................................................131
Configure BFD for Physical Ports.......................................................................................................................... 132
Configure BFD for Static Routes........................................................................................................................... 133
Configure BFD for OSPF.........................................................................................................................................136
Configure BFD for OSPFv3.................................................................................................................................... 139
Configure BFD for IS-IS...........................................................................................................................................140
Configure BFD for BGP...........................................................................................................................................142
Configure BFD for VRRP........................................................................................................................................ 149
Configuring Protocol Liveness................................................................................................................................152
Troubleshooting BFD............................................................................................................................................... 152
8 Border Gateway Protocol IPv4 (BGPv4)....................................................................................................154
Autonomous Systems (AS)...........................................................................................................................................154
Sessions and Peers........................................................................................................................................................ 156
Establish a Session...................................................................................................................................................156
Route Reflectors............................................................................................................................................................ 157
BGP Attributes............................................................................................................................................................... 158
Best Path Selection Criteria....................................................................................................................................159
Weight....................................................................................................................................................................... 160
Local Preference...................................................................................................................................................... 160
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