Users Guide
Congure BFD for VRRP.........................................................................................................................................160
Conguring Protocol Liveness................................................................................................................................ 163
Troubleshooting BFD................................................................................................................................................163
9 Border Gateway Protocol IPv4 (BGPv4).................................................................................................... 165
Autonomous Systems (AS)...........................................................................................................................................165
Sessions and Peers.........................................................................................................................................................167
Establish a Session................................................................................................................................................... 167
Route Reectors.............................................................................................................................................................168
BGP Attributes................................................................................................................................................................169
Best Path Selection Criteria....................................................................................................................................169
Weight.........................................................................................................................................................................171
Local Preference........................................................................................................................................................171
Multi-Exit Discriminators (MEDs)...........................................................................................................................172
Origin..........................................................................................................................................................................173
AS Path...................................................................................................................................................................... 174
Next Hop....................................................................................................................................................................174
Multiprotocol BGP.......................................................................................................................................................... 174
Implement BGP with Dell Networking OS...................................................................................................................175
Additional Path (Add-Path) Support......................................................................................................................175
Advertise IGP Cost as MED for Redistributed Routes........................................................................................ 175
Ignore Router-ID in Best-Path Calculation............................................................................................................ 176
Four-Byte AS Numbers............................................................................................................................................176
AS4 Number Representation.................................................................................................................................. 176
AS Number Migration...............................................................................................................................................178
BGP4 Management Information Base (MIB)........................................................................................................179
Important Points to Remember.............................................................................................................................. 179
Conguration Information..............................................................................................................................................180
BGP Conguration......................................................................................................................................................... 180
Enabling BGP.............................................................................................................................................................181
Conguring AS4 Number Representations........................................................................................................... 184
Conguring Peer Groups.........................................................................................................................................186
Conguring BGP Fast Fall-Over.............................................................................................................................188
Conguring Passive Peering................................................................................................................................... 190
Maintaining Existing AS Numbers During an AS Migration.................................................................................190
Allowing an AS Number to Appear in its Own AS Path........................................................................................191
Enabling Graceful Restart........................................................................................................................................192
Enabling Neighbor Graceful Restart.......................................................................................................................193
Filtering on an AS-Path Attribute........................................................................................................................... 193
Regular Expressions as Filters.................................................................................................................................195
Redistributing Routes.............................................................................................................................................. 196
Enabling Additional Paths........................................................................................................................................ 197
Conguring IP Community Lists............................................................................................................................. 197
Conguring an IP Extended Community List........................................................................................................198
Filtering Routes with Community Lists..................................................................................................................199
Manipulating the COMMUNITY Attribute............................................................................................................200
Contents
7