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Table Of Contents
Configuring Filters Without a Sequence Number.............................................................................................. 120
Configure Layer 2 and Layer 3 ACLs.......................................................................................................................... 120
Assign an IP ACL to an Interface..................................................................................................................................121
Applying an IP ACL...........................................................................................................................................................121
Counting ACL Hits..................................................................................................................................................... 122
Configure Ingress ACLs..................................................................................................................................................122
Configure Egress ACLs.................................................................................................................................................. 123
Applying Egress Layer 3 ACLs (Control-Plane)..................................................................................................123
IP Prefix Lists....................................................................................................................................................................124
Configuration Task List for Prefix Lists................................................................................................................124
ACL Remarks.................................................................................................................................................................... 127
Configuring a Remark............................................................................................................................................... 128
Deleting a Remark......................................................................................................................................................128
ACL Resequencing.......................................................................................................................................................... 129
Resequencing an ACL or Prefix List......................................................................................................................129
Route Maps.......................................................................................................................................................................130
Logging of ACL Processes............................................................................................................................................. 131
Guidelines for Configuring ACL Logging............................................................................................................... 131
Configuring ACL Logging......................................................................................................................................... 132
Flow-Based Monitoring.................................................................................................................................................. 132
Enabling Flow-Based Monitoring............................................................................................................................134
Chapter 8: Bidirectional Forwarding Detection (BFD)................................................................ 136
How BFD Works...............................................................................................................................................................136
BFD Packet Format................................................................................................................................................... 137
BFD Sessions.............................................................................................................................................................. 138
BFD Three-Way Handshake.................................................................................................................................... 139
Session State Changes.............................................................................................................................................140
Important Points to Remember....................................................................................................................................140
Configure BFD..................................................................................................................................................................140
Configure BFD for Physical Ports...........................................................................................................................141
Configure BFD for Static Routes........................................................................................................................... 142
Configure BFD for OSPF......................................................................................................................................... 145
Configure BFD for OSPFv3..................................................................................................................................... 148
Configure BFD for IS-IS............................................................................................................................................151
Configure BFD for BGP............................................................................................................................................153
Configure BFD for VRRP......................................................................................................................................... 159
Configuring Protocol Liveness................................................................................................................................162
Troubleshooting BFD................................................................................................................................................ 162
Establishing Sessions for Static Routes for Default VRF................................................................................ 163
Chapter 9: Border Gateway Protocol (BGP)............................................................................... 165
BGP IP version 4 (BGPv4) Overview......................................................................................................................... 165
BGP Autonomous Systems..................................................................................................................................... 165
AS4 Number Representation...................................................................................................................................167
Four-Byte AS Numbers............................................................................................................................................ 169
BGP router ID............................................................................................................................................................. 169
Sessions and Peers....................................................................................................................................................169
Establish a Session.................................................................................................................................................... 169
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