[c-nsp] vpnv4 export map question

Peter Rathlev peter at rathlev.dk
Fri Nov 18 04:05:31 EST 2011


On Fri, 2011-11-18 at 02:46 -0600, cisconsp at secureobscure.com wrote:
> The intent of the configured export map is to ensure that it only sends the
> default route to the route reflector, for import at downstream PE routers.
...
> However the PE is actually advertising ALL of its routes in the VRF to the
> VPNv4 RR’s, without a route target extended community value:
> 
> RR#show ip bgp vpnv4 rd X.X.X.X:999 32.0.0.0
>>   7018 2686, (received & used)
>     12.89.169.xx from 12.89.169.xx (12.122.124.xx)
>       Origin IGP, localpref 100, valid, external, best
>       mpls labels in/out 227/nolabel
> 
> Is there some misconfiguration with the export map? Why is the 32.0.0.0/8
> prefix being advertised to the RR? Why doesn’t the export map filter it out?

I think that's how it's supposed to work.

Every prefix is advertised, but the RTs decide where they are used. On
the receiving PEs you would have a VRF with "route-target import
649X:999", and that would only match the default route. The others are
sent in the VPNv4 MP-BGP session but not used by the other PE.

-- 
Peter




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