Users Guide

Sessions and Peers......................................................................................................................................................... 167
Establish a Session....................................................................................................................................................167
Route Reectors.............................................................................................................................................................168
Communities...................................................................................................................................................................169
BGP Attributes............................................................................................................................................................... 169
Best Path Selection Criteria......................................................................................................................................169
Weight............................................................................................................................................................................. 171
Local Preference..............................................................................................................................................................171
Multi-Exit Discriminators (MEDs)..............................................................................................................................172
Origin.............................................................................................................................................................................. 173
AS Path...........................................................................................................................................................................173
Next Hop.........................................................................................................................................................................174
Multiprotocol BGP...........................................................................................................................................................174
Implement BGP with Dell Networking OS....................................................................................................................... 174
Additional Path (Add-Path) Support..........................................................................................................................174
Advertise IGP Cost as MED for Redistributed Routes...............................................................................................175
Ignore Router-ID for Some Best-Path Calculations................................................................................................... 175
Four-Byte AS Numbers.............................................................................................................................................175
AS4 Number Representation.....................................................................................................................................176
AS Number Migration......................................................................................................................................................177
BGP4 Management Information Base (MIB)...................................................................................................................179
Important Points to Remember.................................................................................................................................179
Conguration Information............................................................................................................................................... 180
BGP Conguration....................................................................................................................................................180
Enabling BGP...................................................................................................................................................................181
Conguring AS4 Number Representations......................................................................................................................184
Conguring Peer Groups................................................................................................................................................ 185
Conguring BGP Fast Fall-Over......................................................................................................................................188
Conguring Passive Peering........................................................................................................................................... 189
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................................................................................................................................192
Filtering on an AS-Path Attribute.................................................................................................................................... 193
Regular Expressions as Filters...................................................................................................................................194
Filtering BGP Routes Using AS-PATH Information..........................................................................................................196
Redistributing Routes..................................................................................................................................................... 196
Enabling Additional Paths................................................................................................................................................ 197
Conguring IP Community Lists...................................................................................................................................... 197
Filtering Routes with Community Lists............................................................................................................................199
Manipulating the COMMUNITY Attribute....................................................................................................................... 199
Changing MED Attributes............................................................................................................................................... 201
Changing the LOCAL_PREFERENCE Attribute..............................................................................................................201
Changing the NEXT_HOP Attribute...............................................................................................................................202
Changing the WEIGHT Attribute....................................................................................................................................202
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