Administrator Guide

Multi-Exit Discriminators (MEDs)...........................................................................................................................165
Origin..........................................................................................................................................................................166
AS Path...................................................................................................................................................................... 167
Next Hop................................................................................................................................................................... 167
Multiprotocol BGP.......................................................................................................................................................... 167
Implement BGP with Dell Networking OS...................................................................................................................168
Additional Path (Add-Path) Support......................................................................................................................168
Advertise IGP Cost as MED for Redistributed Routes........................................................................................ 168
Ignore Router-ID in Best-Path Calculation............................................................................................................ 169
Four-Byte AS Numbers........................................................................................................................................... 169
AS4 Number Representation.................................................................................................................................. 169
AS Number Migration............................................................................................................................................... 171
BGP4 Management Information Base (MIB)........................................................................................................172
Important Points to Remember.............................................................................................................................. 172
Conguration Information..............................................................................................................................................173
BGP Conguration..........................................................................................................................................................173
Enabling BGP.............................................................................................................................................................174
Conguring AS4 Number Representations............................................................................................................177
Conguring Peer Groups......................................................................................................................................... 179
Conguring BGP Fast Fall-Over..............................................................................................................................181
Conguring Passive Peering................................................................................................................................... 183
Maintaining Existing AS Numbers During an AS Migration................................................................................. 183
Allowing an AS Number to Appear in its Own AS Path....................................................................................... 184
Enabling Graceful Restart....................................................................................................................................... 185
Enabling Neighbor Graceful Restart...................................................................................................................... 186
Filtering on an AS-Path Attribute........................................................................................................................... 186
Regular Expressions as Filters.................................................................................................................................188
Redistributing Routes...............................................................................................................................................189
Enabling Additional Paths........................................................................................................................................ 190
Conguring IP Community Lists.............................................................................................................................190
Conguring an IP Extended Community List.........................................................................................................191
Filtering Routes with Community Lists..................................................................................................................192
Manipulating the COMMUNITY Attribute.............................................................................................................193
Changing MED Attributes....................................................................................................................................... 194
Changing the LOCAL_PREFERENCE Attribute.................................................................................................. 194
Conguring the local System or a Dierent System to be the Next Hop for BGP-Learned Routes.............195
Changing the WEIGHT Attribute............................................................................................................................196
Enabling Multipath....................................................................................................................................................196
Filtering BGP Routes................................................................................................................................................196
Filtering BGP Routes Using Route Maps...............................................................................................................198
Filtering BGP Routes Using AS-PATH Information.............................................................................................. 198
Conguring BGP Route Reectors........................................................................................................................ 199
Aggregating Routes.................................................................................................................................................200
Conguring BGP Confederations.......................................................................................................................... 200
Enabling Route Flap Dampening.............................................................................................................................201
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