Users Guide

Establish a Session...................................................................................................................................................158
Route Reectors.............................................................................................................................................................159
BGP Attributes................................................................................................................................................................160
Best Path Selection Criteria....................................................................................................................................160
Weight........................................................................................................................................................................162
Local Preference.......................................................................................................................................................162
Multi-Exit Discriminators (MEDs)...........................................................................................................................163
Origin..........................................................................................................................................................................164
AS Path......................................................................................................................................................................164
Next Hop................................................................................................................................................................... 165
Multiprotocol BGP..........................................................................................................................................................165
Implement BGP with Dell Networking OS...................................................................................................................166
Additional Path (Add-Path) Support......................................................................................................................166
Advertise IGP Cost as MED for Redistributed Routes........................................................................................ 166
Ignore Router-ID in Best-Path Calculation............................................................................................................ 167
Four-Byte AS Numbers............................................................................................................................................167
AS4 Number Representation.................................................................................................................................. 167
AS Number Migration.............................................................................................................................................. 169
BGP4 Management Information Base (MIB)........................................................................................................170
Important Points to Remember.............................................................................................................................. 170
Conguration Information...............................................................................................................................................171
BGP Conguration.......................................................................................................................................................... 171
Enabling BGP............................................................................................................................................................ 172
Conguring AS4 Number Representations........................................................................................................... 175
Conguring Peer Groups......................................................................................................................................... 176
Conguring BGP Fast Fall-Over............................................................................................................................. 179
Conguring Passive Peering................................................................................................................................... 180
Maintaining Existing AS Numbers During an AS Migration..................................................................................181
Allowing an AS Number to Appear in its Own AS Path....................................................................................... 182
Enabling Graceful Restart........................................................................................................................................183
Enabling Neighbor Graceful Restart.......................................................................................................................184
Filtering on an AS-Path Attribute........................................................................................................................... 184
Regular Expressions as Filters.................................................................................................................................185
Redistributing Routes...............................................................................................................................................187
Enabling Additional Paths.........................................................................................................................................187
Conguring IP Community Lists............................................................................................................................. 188
Conguring an IP Extended Community List........................................................................................................189
Filtering Routes with Community Lists..................................................................................................................190
Manipulating the COMMUNITY Attribute.............................................................................................................190
Changing MED Attributes....................................................................................................................................... 192
Changing the LOCAL_PREFERENCE Attribute.................................................................................................. 192
Changing the NEXT_HOP Attribute...................................................................................................................... 193
Changing the WEIGHT Attribute............................................................................................................................193
Enabling Multipath....................................................................................................................................................194
Filtering BGP Routes................................................................................................................................................194
Filtering BGP Routes Using Route Maps.............................................................................................................. 195
Filtering BGP Routes Using AS-PATH Information.............................................................................................. 196
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