Administrator Guide

Congure BFD................................................................................................................................................................ 149
Congure BFD for Physical Ports.......................................................................................................................... 150
Congure BFD for Static Routes.............................................................................................................................151
Congure BFD for OSPF.........................................................................................................................................154
Congure BFD for OSPFv3.....................................................................................................................................159
Congure BFD for IS-IS...........................................................................................................................................162
Congure BFD for BGP...........................................................................................................................................165
Congure BFD for VRRP..........................................................................................................................................171
Conguring Protocol Liveness.................................................................................................................................174
Troubleshooting BFD................................................................................................................................................ 174
9 Border Gateway Protocol IPv4 (BGPv4).....................................................................................................176
Autonomous Systems (AS)........................................................................................................................................... 176
Sessions and Peers.........................................................................................................................................................178
Establish a Session................................................................................................................................................... 178
Route Reectors.............................................................................................................................................................179
BGP Attributes................................................................................................................................................................180
Best Path Selection Criteria....................................................................................................................................180
Weight........................................................................................................................................................................182
Local Preference.......................................................................................................................................................182
Multi-Exit Discriminators (MEDs)...........................................................................................................................183
Origin..........................................................................................................................................................................184
AS Path......................................................................................................................................................................185
Next Hop................................................................................................................................................................... 185
Multiprotocol BGP..........................................................................................................................................................185
Implement BGP with Dell Networking OS...................................................................................................................186
Additional Path (Add-Path) Support......................................................................................................................186
Advertise IGP Cost as MED for Redistributed Routes........................................................................................ 186
Ignore Router-ID in Best-Path Calculation.............................................................................................................187
Four-Byte AS Numbers............................................................................................................................................187
AS4 Number Representation...................................................................................................................................187
AS Number Migration.............................................................................................................................................. 189
BGP4 Management Information Base (MIB)........................................................................................................190
Important Points to Remember..............................................................................................................................190
Conguration Information.............................................................................................................................................. 191
BGP Conguration.......................................................................................................................................................... 191
Enabling BGP............................................................................................................................................................ 192
Conguring AS4 Number Representations...........................................................................................................195
Conguring Peer Groups......................................................................................................................................... 197
Conguring BGP Fast Fall-Over.............................................................................................................................199
Conguring Passive Peering................................................................................................................................... 201
Maintaining Existing AS Numbers During an AS Migration.................................................................................201
Allowing an AS Number to Appear in its Own AS Path...................................................................................... 202
Enabling Graceful Restart.......................................................................................................................................203
Enabling Neighbor Graceful Restart......................................................................................................................204
Filtering on an AS-Path Attribute.......................................................................................................................... 204
Contents
7