[c-nsp] bgp communities over vpn mpls

[Oliver Boehmer (oboehmer)]

> It depends on the provider.  Extended communities are also used in
vpn/vrf
> route filters so honoring any community already seen on a customer
route is
> dangerous.

actually: RFC4364 deals with route-target extcomms already attached to
the eBGP customer routes, and removes all of those which are not
configured as RT export in the customer VRF on the PE. This capability
allows the customer to specify only a subset of VRFs which should see
the pfx. Not really useful and not widely used as it would require the
customer to know exactly about the SP's RT import/export
structure/assignments, but I wanted to mention that RT extcomm's
received from the customer do not compromise the route
isolation/segmentation property of BGP-L3VPN..

	oli