BGP routes not showing up

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Jun 20th, 2008
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I have a lab environment where I'm duplicating our production network (to a small scale). I have the following:


CE#1 PE#1 PE#2 CE#2

I have the 3550's participating at CE's to the C6503 ad ME6524 as PE's. At each CE, I can see the other CE's uplink subnet, but not the subnet assigned to the loopback interface on the other CE.

I have included the relevant portions of the configurations for each of the switches involved. I'm certain that I'm overlooking something very simple, but I cannot find why the routes don't propagate to the other side. Any help is greatly appreciated!


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Overall Rating: 4 (2 ratings)
waleed_amer Fri, 06/20/2008 - 14:10
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Hi Michael,

the same AS number is used in CE1 & CE2 so they will not accept routes coming from the same AS number so you need to configure: neighbor x.x.x.x as-override into PE1 & PE2 under address-family ipv4 vrf Customer1 so the PE will send bgp update with AS [10 10] instead of [10 1001].


mohammedmahmoud Sat, 06/21/2008 - 00:50
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Hi All,

Just to add to Waleed's suggestion, you can also use the allowas-in feature on the CE router (to disable the AS-Path check in the first place), but with either cases i'd recommend you to configure SOO if a backdoor is present between VPN sites or if a site is dual-homed (sites that are connected to two or more PE routers) since you have overriden the eBGP loop prevention mechanisms.


Mohammed Mahmoud.


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