Deployment Guide

Table Of Contents
Origin..............................................................................................................................................................................171
AS Path......................................................................................................................................................................... 171
Next Hop...................................................................................................................................................................... 172
Multiprotocol BGP........................................................................................................................................................... 172
Implement BGP ............................................................................................................................................................... 172
Advertise IGP Cost as MED for Redistributed Routes..................................................................................... 173
Ignore Router-ID for Some Best-Path Calculations.......................................................................................... 173
Four-Byte AS Numbers.............................................................................................................................................173
AS4 Number Representation...................................................................................................................................174
AS Number Migration................................................................................................................................................175
BGP4 Management Information Base (MIB)...................................................................................................... 176
Important Points to Remember.............................................................................................................................. 177
Configuration Information..............................................................................................................................................177
BGP Configuration...........................................................................................................................................................178
Enabling BGP.............................................................................................................................................................. 178
Configuring AS4 Number Representations.......................................................................................................... 181
Configuring Peer Groups..........................................................................................................................................183
Configuring BGP Fast Fail-Over.............................................................................................................................185
Configuring Passive Peering................................................................................................................................... 186
Maintaining Existing AS Numbers During an AS Migration..............................................................................187
Allowing an AS Number to Appear in its Own AS Path.................................................................................... 187
Filtering on an AS-Path Attribute.......................................................................................................................... 188
Regular Expressions as Filters................................................................................................................................ 189
Redistributing Routes............................................................................................................................................... 190
Enabling Additional Paths......................................................................................................................................... 191
Configuring IP Community Lists..............................................................................................................................191
Configuring an IP Extended Community List...................................................................................................... 192
Filtering Routes with Community Lists.................................................................................................................193
Manipulating the COMMUNITY Attribute............................................................................................................194
Changing MED Attributes........................................................................................................................................195
Changing the LOCAL_PREFERENCE Attribute.................................................................................................195
Configuring the local System or a Different System to be the Next Hop for BGP-Learned Routes....196
Changing the WEIGHT Attribute........................................................................................................................... 196
Enabling Multipath..................................................................................................................................................... 197
Filtering BGP Routes.................................................................................................................................................197
Filtering BGP Routes Using Route Maps............................................................................................................. 198
Filtering BGP Routes Using AS-PATH Information........................................................................................... 198
Configuring BGP Route Reflectors....................................................................................................................... 199
Aggregating Routes...................................................................................................................................................199
Configuring BGP Confederations..........................................................................................................................200
Enabling Route Flap Dampening............................................................................................................................200
Changing BGP Timers..............................................................................................................................................202
Setting the extended timer.....................................................................................................................................203
Enabling BGP Neighbor Soft-Reconfiguration...................................................................................................203
Enabling or disabling BGP neighbors....................................................................................................................204
Route Map Continue................................................................................................................................................ 205
Enabling MBGP Configurations................................................................................................................................... 206
Configure IPv6 NH Automatically for IPv6 Prefix Advertised over IPv4 Neighbor.................................. 206
BGP Regular Expression Optimization.......................................................................................................................207
Debugging BGP............................................................................................................................................................... 207
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