[c-nsp] BGP router-id - Chaos?

[Shimol Shah ( Cisco )]

I tried in my lab with two boxes

28xx-----76xx

28xx is running 12.4(15)T9
76xx is running 12.2(33)SRB6
eBGP between the boxes.

I changed the route-id manually on 28xx
========================================

2800#sh ip bgp sum
BGP router identifier 10.10.10.1, local AS number 1020
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down 
State/PfxRcd
2.2.2.2         4  1021      14      16        1    0    0 00:01:46        0
10.10.10.2      4  1021      14      16        1    0    0 00:01:34        0
2800#
2800#
2800#sh run | s bgp
router bgp 1020
  no synchronization
  bgp router-id 10.10.10.1
  bgp log-neighbor-changes
  neighbor 2.2.2.2 remote-as 1021
  neighbor 2.2.2.2 ebgp-multihop 10
  neighbor 2.2.2.2 update-source Loopback0
  neighbor 10.10.10.2 remote-as 1021
  no auto-summary
2800#
2800#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2800(config)#
2800(config)#router bgp 1020
2800(config-router)#bgp rout
2800(config-router)#bgp router-id 1.1.1.1
2800(config-router)#end
2800#
*Jul 15 14:11:21.199 EST: %BGP-5-ADJCHANGE: neighbor 2.2.2.2 Down Router 
ID changed
*Jul 15 14:11:21.199 EST: %BGP-5-ADJCHANGE: neighbor 10.10.10.2 Down 
Router ID changed
*Jul 15 14:11:21.211 EST: %SYS-5-CONFIG_I: Configured from console by 
console
*Jul 15 14:11:21.239 EST: %BGP-5-ADJCHANGE: neighbor 2.2.2.2 Up
*Jul 15 14:11:21.251 EST: %BGP-5-ADJCHANGE: neighbor 10.10.10.2 Up
2800#

0#
2800#sh ip bgp sum
BGP router identifier 1.1.1.1, local AS number 1020
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down 
State/PfxRcd
2.2.2.2         4  1021      17      21        1    0    0 00:00:28        0
10.10.10.2      4  1021      17      21        1    0    0 00:00:28        0
2800#


I then tried in on 7600
========================


7600#sh ip bgp sum
Load for five secs: 0%/0%; one minute: 3%; five minutes: 2%
Time source is hardware calendar, *18:13:06.279 EST Wed Jul 15 2009
BGP router identifier 10.10.10.2, local AS number 1021
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down 
State/PfxRcd
1.1.1.1         4  1020       4       3        1    0    0 00:00:06        0
10.10.10.1      4  1020       4       3        1    0    0 00:00:06        0
7600#
7600#
7600#sh run | b router bgp
router bgp 1021
  no synchronization
  bgp router-id 10.10.10.2
  bgp log-neighbor-changes
  neighbor 1.1.1.1 remote-as 1020
  neighbor 1.1.1.1 ebgp-multihop 10
  neighbor 1.1.1.1 update-source Loopback0
  neighbor 10.10.10.1 remote-as 1020
  no auto-summary
!
7600#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
7600(config)#router bgp 1021
7600(config-router)#bgp route
7600(config-router)#bgp router-id 2.2.2.2
7600(config-router)#end
7600#
*Jul 15 18:13:34.819: %BGP-5-ADJCHANGE: neighbor 1.1.1.1 Down Router ID 
changed
*Jul 15 18:13:34.819: %BGP-5-ADJCHANGE: neighbor 10.10.10.1 Down Router 
ID changed
*Jul 15 18:13:35.475: %SYS-5-CONFIG_I: Configured from console by console
7600#
7600#
7600#
*Jul 15 18:13:50.159: %BGP-5-ADJCHANGE: neighbor 10.10.10.1 Up
7600#
*Jul 15 18:13:53.287: %BGP-5-ADJCHANGE: neighbor 1.1.1.1 Up
7600#
7600#sh ip bgp sum
Load for five secs: 1%/0%; one minute: 2%; five minutes: 2%
Time source is hardware calendar, *18:13:57.819 EST Wed Jul 15 2009
BGP router identifier 2.2.2.2, local AS number 1021
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down 
State/PfxRcd
1.1.1.1         4  1020       4       3        1    0    0 00:00:04        0
10.10.10.1      4  1020       4       3        1    0    0 00:00:07        0
7600#



Hope that helps.

Shimol




Jeff Cartier wrote:
> Just checking something that I haven't been able to verify online...
> 
>  
> 
> Changing the bgp router-id manually will require you to clear the bgp
> sessions?  Correct?
> 
>  
> 
> Thanks!!!
> 
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