[j-nsp] vrf-export practical proposals welcome....

[Stefan Fouant]

> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net [mailto:juniper-nsp-
> bounces at puck.nether.net] On Behalf Of Peter Krupl
> Sent: Friday, April 29, 2011 7:55 AM
> To: juniper-nsp at puck.nether.net
> Subject: [j-nsp] vrf-export practical proposals welcome....
> 
> Hi Group,
> 
> I trying to think of a practical solution for communities to be applied
> to VRF routes.
> We have a mpls network consisting of several MX'es as PE routers. The
> PE routers have
> BGP PE-CE perrings and off course PE-PE peerings.
> 
> Our advertising of routes to external peers is controlled by
> communities..
> 
> Applying a community directly to a static route is possible albeit
> ugly, since this
> spreads community assignment to both static routes and policy
> statements.

You could use the internal 'tag' statement on the static routes, and then
simply match on 'protocol static' and 'tag x' for your export policy.  Then
set the communities in your action statement.  This would resolve/remove the
issue of community assignments on the statics. 

> Applying a community to a direct(connected) route seems only to be
> possible
> by applying a vrf-export policy for the PE-PE sessions, and applying a
> policy to
> the PE-CE neighbours.
> 
> For the sake of consistency i would strongly prefer a solution where
> theese are only defined
> in a single place. So im thinking of a solution where the setting of
> communities is in a seperate policy,
> and then several policies are applied where needed.
> 
> Policy1, apply route target (this is necessary in a vrf-export policy)
> Policy2, apply communities according to route filter.
> Policy3, filter based on communities (even those set by policy2, is
> this even possible)

This should be possible so long as you don't have a terminating action in
your policy term.  Use of the 'next term' and 'next policy' can assist you
in controlling the flow of policy evaluation to ensure that once a community
is set a subsequent term can be performed to perform additional filtering
based on those communities, etc.

HTHs.

Stefan Fouant, CISSP, JNCIEx2
www.shortestpathfirst.net
GPG Key ID: 0xB4C956EC