Concept Guide

Applying Egress Layer 3 ACLs (Control-Plane)..................................................................................................... 116
IP Prex Lists...................................................................................................................................................................116
Implementation Information..................................................................................................................................... 117
Conguration Task List for Prex Lists................................................................................................................... 117
ACL Remarks.................................................................................................................................................................. 120
Conguring a Remark............................................................................................................................................... 121
Deleting a Remark.....................................................................................................................................................121
ACL Resequencing......................................................................................................................................................... 122
Resequencing an ACL or Prex List.......................................................................................................................122
Route Maps..................................................................................................................................................................... 124
Implementation Information.....................................................................................................................................124
Flow-Based Monitoring..................................................................................................................................................124
Behavior of Flow-Based Monitoring.......................................................................................................................124
Enabling Flow-Based Monitoring............................................................................................................................126
Conguring IP Mirror Access Group.............................................................................................................................127
Sample Conguration...............................................................................................................................................127
Example of viewing IP mirror–access–group applied to an Interface................................................................128
7 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............................................................................................................................136
Congure BFD for IPv6 Static Routes...................................................................................................................140
Congure BFD for OSPF.........................................................................................................................................142
Congure BFD for OSPFv3.....................................................................................................................................148
Congure BFD for IS-IS............................................................................................................................................151
Congure BFD for BGP...........................................................................................................................................153
Congure BFD for VRRP......................................................................................................................................... 161
Conguring Protocol Liveness................................................................................................................................ 163
8 Border Gateway Protocol (BGP)................................................................................................................ 164
Border Gateway Protocol version 4 (BGPv4).............................................................................................................164
Autonomous Systems (AS)...........................................................................................................................................164
AS4 Number Representation.................................................................................................................................. 166
Four-Byte AS Numbers............................................................................................................................................168
Multiprotocol BGP..........................................................................................................................................................168
MBGP for IPv4 MulticastBGP Address Family modelIPv4 and IPv6 address family....................................... 169
Sessions and Peers........................................................................................................................................................ 169
Establish a Session...................................................................................................................................................169
Implementing BGP global and address family............................................................................................................. 170
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