Users Guide

Multi-Exit Discriminators (MEDs)...........................................................................................................................164
Origin..........................................................................................................................................................................165
AS Path......................................................................................................................................................................166
Next Hop................................................................................................................................................................... 166
Multiprotocol BGP..........................................................................................................................................................166
Implement BGP with Dell Networking OS...................................................................................................................167
Additional Path (Add-Path) Support...................................................................................................................... 167
Advertise IGP Cost as MED for Redistributed Routes.........................................................................................167
Ignore Router-ID in Best-Path Calculation............................................................................................................ 168
Four-Byte AS Numbers............................................................................................................................................168
AS4 Number Representation.................................................................................................................................. 168
AS Number Migration...............................................................................................................................................170
BGP4 Management Information Base (MIB).........................................................................................................171
Important Points to Remember...............................................................................................................................171
Conguration Information..............................................................................................................................................172
BGP Conguration..........................................................................................................................................................172
Enabling BGP............................................................................................................................................................ 173
Conguring AS4 Number Representations........................................................................................................... 176
Conguring Peer Groups......................................................................................................................................... 178
Conguring BGP Fast Fall-Over.............................................................................................................................180
Conguring Passive Peering................................................................................................................................... 182
Maintaining Existing AS Numbers During an AS Migration................................................................................. 182
Allowing an AS Number to Appear in its Own AS Path....................................................................................... 183
Enabling Graceful Restart........................................................................................................................................184
Enabling Neighbor Graceful Restart...................................................................................................................... 185
Filtering on an AS-Path Attribute........................................................................................................................... 185
Regular Expressions as Filters.................................................................................................................................187
Redistributing Routes...............................................................................................................................................188
Enabling Additional Paths........................................................................................................................................ 189
Conguring IP Community Lists............................................................................................................................. 189
Conguring an IP Extended Community List........................................................................................................190
Filtering Routes with Community Lists...................................................................................................................191
Manipulating the COMMUNITY Attribute.............................................................................................................192
Changing MED Attributes....................................................................................................................................... 193
Changing the LOCAL_PREFERENCE Attribute.................................................................................................. 193
Conguring the local System or a Dierent System to be the Next Hop for BGP-Learned Routes............. 194
Changing the WEIGHT Attribute............................................................................................................................195
Enabling Multipath....................................................................................................................................................195
Filtering BGP Routes................................................................................................................................................195
Filtering BGP Routes Using Route Maps...............................................................................................................197
Filtering BGP Routes Using AS-PATH Information...............................................................................................197
Conguring BGP Route Reectors........................................................................................................................ 198
Aggregating Routes..................................................................................................................................................199
Conguring BGP Confederations...........................................................................................................................199
Enabling Route Flap Dampening............................................................................................................................200
Contents
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