Users Guide

Troubleshooting BFD............................................................................................................................................... 163
9 Border Gateway Protocol IPv4 (BGPv4)....................................................................................................165
Autonomous Systems (AS).......................................................................................................................................... 165
Sessions and Peers.........................................................................................................................................................167
Establish a Session................................................................................................................................................... 167
Route Reflectors............................................................................................................................................................ 168
BGP Attributes............................................................................................................................................................... 169
Best Path Selection Criteria....................................................................................................................................170
Weight........................................................................................................................................................................ 171
Local Preference....................................................................................................................................................... 171
Multi-Exit Discriminators (MEDs)...........................................................................................................................172
Origin..........................................................................................................................................................................173
AS Path......................................................................................................................................................................174
Next Hop................................................................................................................................................................... 174
Multiprotocol BGP..........................................................................................................................................................174
Implement BGP with Dell Networking OS...................................................................................................................175
Additional Path (Add-Path) Support..................................................................................................................... 175
Advertise IGP Cost as MED for Redistributed Routes........................................................................................175
Ignore Router-ID in Best-Path Calculation............................................................................................................176
Four-Byte AS Numbers........................................................................................................................................... 176
AS4 Number Representation.................................................................................................................................. 176
AS Number Migration.............................................................................................................................................. 178
BGP4 Management Information Base (MIB)........................................................................................................179
Important Points to Remember..............................................................................................................................179
Configuration Information............................................................................................................................................. 180
BGP Configuration......................................................................................................................................................... 180
Enabling BGP.............................................................................................................................................................181
Configuring AS4 Number Representations...........................................................................................................184
Configuring Peer Groups.........................................................................................................................................186
Configuring BGP Fast Fall-Over.............................................................................................................................188
Configuring Passive Peering...................................................................................................................................190
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...................................................................................................................... 193
Filtering on an AS-Path Attribute...........................................................................................................................193
Regular Expressions as Filters................................................................................................................................ 195
Redistributing Routes.............................................................................................................................................. 196
Enabling Additional Paths........................................................................................................................................ 197
Configuring IP Community Lists............................................................................................................................. 197
Configuring an IP Extended Community List........................................................................................................198
Filtering Routes with Community Lists..................................................................................................................199
Manipulating the COMMUNITY Attribute............................................................................................................200
Changing MED Attributes....................................................................................................................................... 201
Changing the LOCAL_PREFERENCE Attribute.................................................................................................. 201
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