Administrator Guide

Table Of Contents
Configuring a Standard IP ACL Filter......................................................................................................................... 118
Configure an Extended IP ACL......................................................................................................................................... 119
Configuring Filters with a Sequence Number........................................................................................................... 119
Configuring Filters Without a Sequence Number.....................................................................................................121
Configure Layer 2 and Layer 3 ACLs...............................................................................................................................122
Assign an IP ACL to an Interface..................................................................................................................................... 123
Applying an IP ACL.............................................................................................................................................................123
Counting ACL Hits....................................................................................................................................................... 123
Configure Ingress ACLs.....................................................................................................................................................124
Configure Egress ACLs..................................................................................................................................................... 124
Applying Egress Layer 3 ACLs (Control-Plane)....................................................................................................... 125
IP Prefix Lists......................................................................................................................................................................125
Configuration Task List for Prefix Lists.....................................................................................................................126
ACL Remarks......................................................................................................................................................................129
Configuring a Remark.................................................................................................................................................. 129
Deleting a Remark........................................................................................................................................................129
ACL Resequencing.............................................................................................................................................................130
Resequencing an ACL or Prefix List.......................................................................................................................... 130
Route Maps......................................................................................................................................................................... 131
8 Bidirectional Forwarding Detection (BFD)................................................................................... 133
How BFD Works.................................................................................................................................................................133
BFD Packet Format..................................................................................................................................................... 134
BFD Sessions................................................................................................................................................................135
BFD Three-Way Handshake....................................................................................................................................... 136
Session State Changes................................................................................................................................................137
Important Points to Remember........................................................................................................................................137
Configure BFD.................................................................................................................................................................... 137
Configure BFD for Physical Ports.............................................................................................................................. 138
Configure BFD for Static Routes...............................................................................................................................140
Configure BFD for IPv6 Static Routes...................................................................................................................... 143
Configure BFD for OSPF............................................................................................................................................ 145
Configure BFD for OSPFv3........................................................................................................................................150
Configure BFD for IS-IS.............................................................................................................................................. 152
Configure BFD for BGP...............................................................................................................................................154
Configure BFD for VRRP.............................................................................................................................................161
Configuring Protocol Liveness....................................................................................................................................163
9 Border Gateway Protocol (BGP).................................................................................................164
BGP IP version 4 (BGPv4) Overview..............................................................................................................................164
BGP Autonomous Systems.........................................................................................................................................164
AS4 Number Representation......................................................................................................................................166
Four-Byte AS Numbers...............................................................................................................................................168
BGP router ID............................................................................................................................................................... 168
Sessions and Peers...................................................................................................................................................... 168
Establish a Session.......................................................................................................................................................168
BGP Attributes for selecting Best Path....................................................................................................................169
Multiprotocol BGP........................................................................................................................................................174
BGP global and address family configuration........................................................................................................... 175
6
Contents