10-15-2010 08:25 AM - edited 03-04-2019 10:08 AM
Hi,
We have site that is only receiving ~2000 of the ~4000 prefixes we pump around the country. A sh ip bgp nei is showing a lot of inbound AS_PATH loops, but the PE vendor does not see any problem (he said). These sites are all "cookie cutter" deployments with the following similar configs:
router bgp 1111 (obvious fake!)
no synchronization
bgp log-neighbor-changes
network 10.x.x.1 mask 255.255.255.0
neighbor 10.x.x.2 remote-as 2222
distance bgp 200 200 200
no auto-summary
I am not sure where to start looking!
Any clues?
Dave
Solved! Go to Solution.
10-15-2010 11:27 AM
Hi ,
you can test if this is the problem , by disabling this requirement : neighbor x.x.x.x allowas-in
If you will see your prefixes , then you will see also the as-path , and this is the answer to your problem.
Dan
10-15-2010 08:45 AM
hi dave
Are all the CE's located in AS1111 and all the PE's in AS2222?
If there are that many AS-PATH loops and the scenario is like in my question - maybe the PE-vendor missed to configure "neighbor x.x.x.x as-override" on some of the BGP peerings to your CE's.
HTH
Marcel
10-15-2010 10:04 AM
Thanks Marcel,
There are several 1111's and 2222's. That's a great idea about the as-overide.. I will open a ticket with the provider and ask that question.
Dave
10-15-2010 11:27 AM
Hi ,
you can test if this is the problem , by disabling this requirement : neighbor x.x.x.x allowas-in
If you will see your prefixes , then you will see also the as-path , and this is the answer to your problem.
Dan
10-17-2010 05:43 AM
Good point, Dan
10-20-2010 08:12 AM
That was very informative .. all the missing prefixes show up a path of *> x.x.x.x. 2222 1111 ?
So I need to look at the configurations of other AS2222 routers to find my problem?
Dave
10-20-2010 08:40 AM
Yes - Enable AS-Override on every PE-to-CE-peering:
neighbor x.x.x.x remote-as 1111
neighbor x.x.x.x as-override
HTH
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