[c-nsp] MPLS VRF Route import/export

[Piotr Marecki]

On Wed, Nov 02, 2005 at 11:36:25AM +0100, Anton.Schweitzer at o2.com wrote:
> Hi,
> 
> i need to import just one prefix in Site B which i have learnt in Site A, 
> not all the other prefixes from A
> 
> Is there a possibility to filter prefixes with are imported by an 
> "route-target import xxx:xxx" statement
> 
> As far as i understand when i use an import map, this influences then all 
> the import statements vor the vrf
> and i need to allow then all the prefixes from all the import statements.
> 
> I tried to tag the prefixes with a second rt on the incoming interface to 
> the vrf, which is not supported.
>
Ehlo , 

I'm not sure that i correctly understand your problem , however assuming that  :

1) You have several sites connected to VRF  x , and one of them is Site B. Site A exports
   several prefixes to  MP-BGP , which in turn are imported into VRF X by matching RT community.
   However you don't want all SiteA prefixes to enter Site B  , just one of them. In the same time
   other sites connected to VRF x needs all route information - that's why you cant use vrf "import map"
   statement. SOlution is to attach standard community to that particular prefix in site A and then filter
   route distribution to site B based on that information ( in CE-PE session itself - i assume that you 
   are using BGP - in other cases you might need to use external tag in OSPF/EIGRP )
2) You don't have other sites besides SIteB connected to VRF X instance - in that case you can use "import map"
   statement - again filtering can be based on standard community etc. 

In both cases when using standard community along with extended in VPN-IPv4 family , remember to configure
neighbor x.x.x.x send-community both under address-family vpnv4.

regards,

Piotr Marecki