Users Guide

AS4 Number Representation......................................................................................................................... 160
AS Number Migration.......................................................................................................................................162
BGP4 Management Information Base (MIB)...............................................................................................164
Important Points to Remember.....................................................................................................................164
Configuration Information................................................................................................................................... 165
BGP Configuration................................................................................................................................................. 165
Enabling BGP.....................................................................................................................................................166
Configuring AS4 Number Representations.................................................................................................169
Configuring Peer Groups................................................................................................................................ 170
Configuring BGP Fast Fall-Over.....................................................................................................................173
Configuring Passive Peering...........................................................................................................................174
Maintaining Existing AS Numbers During an AS Migration...................................................................... 175
Allowing an AS Number to Appear in its Own AS Path.............................................................................176
Enabling Graceful Restart................................................................................................................................177
Enabling Neighbor Graceful Restart............................................................................................................. 178
Filtering on an AS-Path Attribute...................................................................................................................178
Regular Expressions as Filters.........................................................................................................................179
Redistributing Routes....................................................................................................................................... 181
Enabling Additional Paths................................................................................................................................181
Configuring IP Community Lists................................................................................................................... 182
Configuring an IP Extended Community List............................................................................................. 183
Filtering Routes with Community Lists........................................................................................................ 184
Manipulating the COMMUNITY Attribute....................................................................................................184
Changing MED Attributes............................................................................................................................... 186
Changing the LOCAL_PREFERENCE Attribute...........................................................................................186
Configuring the local System or a Different System to be the Next Hop for BGP-Learned
Routes................................................................................................................................................................. 187
Changing the WEIGHT Attribute................................................................................................................... 187
Enabling Multipath............................................................................................................................................188
Filtering BGP Routes........................................................................................................................................ 188
Filtering BGP Routes Using Route Maps......................................................................................................189
Filtering BGP Routes Using AS-PATH Information....................................................................................190
Configuring BGP Route Reflectors................................................................................................................191
Aggregating Routes.......................................................................................................................................... 191
Configuring BGP Confederations................................................................................................................. 192
Enabling Route Flap Dampening...................................................................................................................192
Changing BGP Timers..................................................................................................................................... 194
Enabling BGP Neighbor Soft-Reconfiguration...........................................................................................195
Route Map Continue........................................................................................................................................196
Enabling MBGP Configurations...........................................................................................................................196
BGP Regular Expression Optimization...............................................................................................................197
Debugging BGP.......................................................................................................................................................197
Storing Last and Bad PDUs.............................................................................................................................198
Capturing PDUs................................................................................................................................................ 199
PDU Counters...................................................................................................................................................200
Sample Configurations......................................................................................................................................... 200
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