Users Guide

Implementation Information.......................................................................................................................... 112
Configuration Task List for Prefix Lists..........................................................................................................112
ACL Resequencing..................................................................................................................................................115
Resequencing an ACL or Prefix List.............................................................................................................. 116
Route Maps...............................................................................................................................................................117
Implementation Information.......................................................................................................................... 117
Flow-Based Monitoring Support for ACLs.........................................................................................................117
Behavior of Flow-Based Monitoring.............................................................................................................118
Enabling Flow-Based Monitoring.................................................................................................................. 119
7 Bidirectional Forwarding Detection (BFD)......................................................................................................121
How BFD Works...................................................................................................................................................... 121
BFD Packet Format...........................................................................................................................................122
BFD Sessions......................................................................................................................................................123
BFD Three-Way Handshake........................................................................................................................... 124
Session State Changes.....................................................................................................................................126
Important Points to Remember.......................................................................................................................... 126
Configure BFD.........................................................................................................................................................126
Configure BFD for Physical Ports.................................................................................................................. 127
Configure BFD for Static Routes................................................................................................................... 130
Configure BFD for OSPF..................................................................................................................................132
Configure BFD for OSPFv3............................................................................................................................. 134
Configure BFD for IS-IS...................................................................................................................................136
Configure BFD for BGP................................................................................................................................... 138
Configure BFD for VRRP................................................................................................................................. 145
Configuring Protocol Liveness.......................................................................................................................147
Troubleshooting BFD.......................................................................................................................................147
8 Border Gateway Protocol IPv4 (BGPv4)......................................................................................................... 149
Autonomous Systems (AS)................................................................................................................................... 149
Sessions and Peers..................................................................................................................................................151
Establish a Session............................................................................................................................................152
Route Reflectors..................................................................................................................................................... 152
BGP Attributes......................................................................................................................................................... 153
Best Path Selection Criteria............................................................................................................................ 154
Weight................................................................................................................................................................. 156
Local Preference...............................................................................................................................................156
Multi-Exit Discriminators (MEDs)...................................................................................................................156
Origin...................................................................................................................................................................157
AS Path................................................................................................................................................................ 158
Next Hop............................................................................................................................................................ 158
Multiprotocol BGP..................................................................................................................................................158
Implement BGP with Dell Networking OS........................................................................................................ 159
Additional Path (Add-Path) Support..............................................................................................................159
Advertise IGP Cost as MED for Redistributed Routes............................................................................... 159
Ignore Router-ID in Best-Path Calculation................................................................................................ 160
Four-Byte AS Numbers................................................................................................................................... 160
9.10(0.1)
6