[c-nsp] Interesting Problem - MPBGP Filtering

David Freedman david.freedman at uk.clara.net
Mon Nov 12 07:35:48 EST 2007




Marko Milivojevic wrote:
> Sure thing.
> 
> PE1 - PE.PE.PE.225
> PE2 - PE.PE.PE.226
> 
> R1#sh ip bgp vpn all PE.PE.PE.225
> BGP routing table entry for AS:1:X.X.X.X.0/19, version 57
> Paths: (2 available, best #1, table Internet)
>   Not advertised to any peer
>   Local
>     PE.PE.PE.225 (metric 101) from PE.PE.PE.225 (PE.PE.PE.225)
>       Origin IGP, metric 0, localpref 1000, valid, internal, best
>       Community: AS:0
>       Extended Community: RT:AS:1
>       mpls labels in/out nolabel/55

<snip>

Well, this is your problem then, you are tagging your PE /32s
with extcommunity AS:1 and standard community AS:0,
the combination of which are permitted in the first entry
of your route-map.

!
ip extcommunity-list standard AS-Internet permit rt AS:1
ip community-list standard AS-Originated-Routes permit AS:0
!
route-map PE-in permit 5
!
  match extcommunity AS-Internet
  match community AS-Originated-Routes
!

Unless I'm misreading this?

Dave.




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