Users Guide

Establish a Session...................................................................................................................................................165
Route Reectors.............................................................................................................................................................166
BGP Attributes................................................................................................................................................................167
Best Path Selection Criteria.................................................................................................................................... 167
Weight........................................................................................................................................................................169
Local Preference.......................................................................................................................................................169
Multi-Exit Discriminators (MEDs)...........................................................................................................................170
Origin...........................................................................................................................................................................171
AS Path...................................................................................................................................................................... 172
Next Hop................................................................................................................................................................... 172
Multiprotocol BGP.......................................................................................................................................................... 172
Implement BGP with Dell Networking OS...................................................................................................................173
Additional Path (Add-Path) Support......................................................................................................................173
Advertise IGP Cost as MED for Redistributed Routes.........................................................................................173
Ignore Router-ID in Best-Path Calculation.............................................................................................................174
Four-Byte AS Numbers............................................................................................................................................174
AS4 Number Representation...................................................................................................................................174
AS Number Migration...............................................................................................................................................176
BGP4 Management Information Base (MIB)........................................................................................................ 177
Important Points to Remember...............................................................................................................................177
Conguration Information..............................................................................................................................................178
BGP Conguration..........................................................................................................................................................178
Enabling BGP............................................................................................................................................................ 179
Conguring AS4 Number Representations........................................................................................................... 182
Conguring Peer Groups......................................................................................................................................... 184
Conguring BGP Fast Fall-Over.............................................................................................................................186
Conguring Passive Peering................................................................................................................................... 188
Maintaining Existing AS Numbers During an AS Migration................................................................................. 188
Allowing an AS Number to Appear in its Own AS Path....................................................................................... 189
Enabling Graceful Restart....................................................................................................................................... 190
Enabling Neighbor Graceful Restart....................................................................................................................... 191
Filtering on an AS-Path Attribute............................................................................................................................191
Regular Expressions as Filters.................................................................................................................................193
Redistributing Routes...............................................................................................................................................194
Enabling Additional Paths........................................................................................................................................ 195
Conguring IP Community Lists.............................................................................................................................195
Conguring an IP Extended Community List........................................................................................................196
Filtering Routes with Community Lists.................................................................................................................. 197
Manipulating the COMMUNITY Attribute.............................................................................................................198
Changing MED Attributes....................................................................................................................................... 199
Changing the LOCAL_PREFERENCE Attribute.................................................................................................. 199
Conguring the local System or a Dierent System to be the Next Hop for BGP-Learned Routes............ 200
Changing the WEIGHT Attribute............................................................................................................................201
Enabling Multipath....................................................................................................................................................201
Filtering BGP Routes................................................................................................................................................201
Contents
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