ā07-04-2013 01:59 AM - edited ā03-04-2019 08:22 PM
Dear all,
I have 3 routers (RT01, RT02 and RT03) running iBGP (AS-1001) and Each router connects to a eBGP neighbor(RT-A, RT-B and RT-c). (topology is as attached PNG file)
Problem I encounter is:
RT01 can get routing information from RT02 itself and RT-B(AS-1003)
RT03 can get routing information from RT02 itself and RT-B(AS-1003)
RT02 can get all routing information from both RT03 including RT-C and RT01including RT-A
but
RT01 can not get routing information from RT03 including routing from RT-C(AS-1004)
RT03 can not get routing information from RT01 including routing from RT-A(AS-1002)
I think it is because RT02 does not advertise routing information which is learned from one neighbor to another iBGP neighbor. (i.e. RT02 does not pass routing learned from RT03/RT-C to RT01, and also does not pass routing learned from RT01/RT-A to RT03)
any advice how to resolve it will be appreciated. Thanks!
Solved! Go to Solution.
ā07-04-2013 02:10 AM
Hi,
in your AS 1001, just do a full mesh of iBGP neighbours: r1-r2,r1-r3,r2-r3
Regards
Alain
Don't forget to rate helpful posts.
ā07-04-2013 03:04 AM
You have to use a iBGP full mesh, or configure R2 as route-reflector.
bests
stefano
ā07-04-2013 03:16 AM
stefano and alain are correct,
bgp rules state an ibgp neighbour will not advertise ibgp learned routes to another ibgp peer, (without the above suggestions or confenderations)
Regards Neil
http://uk.linkedin.com/pub/neil-grant/20/5b0/267
ā07-04-2013 11:21 AM
There is not really much else to add to what has already been stated, but I did find a link that may help provide more details:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml
ā07-04-2013 02:10 AM
Hi,
in your AS 1001, just do a full mesh of iBGP neighbours: r1-r2,r1-r3,r2-r3
Regards
Alain
Don't forget to rate helpful posts.
ā07-04-2013 03:04 AM
You have to use a iBGP full mesh, or configure R2 as route-reflector.
bests
stefano
ā07-04-2013 03:16 AM
stefano and alain are correct,
bgp rules state an ibgp neighbour will not advertise ibgp learned routes to another ibgp peer, (without the above suggestions or confenderations)
Regards Neil
http://uk.linkedin.com/pub/neil-grant/20/5b0/267
ā07-04-2013 11:21 AM
There is not really much else to add to what has already been stated, but I did find a link that may help provide more details:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml
ā07-04-2013 08:50 PM
Thanks all for prompt response and clear clarification.
Since RT01 locates in different site and is unable to do full mesh with other iBGP neighbors, I will study all the information you provided first and try to configure R2 as route-reflector as adviced.
Thanks!!
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