[c-nsp] Filtering prefixes in mpBGP

[Pshem Kowalczyk]

Hi,

We use route servers to mesh all the PEs. On the route server I can
see that all the prefixes (even without the RT, just with RD) are
learnt (or rather received), that causes unnecessary traffic amongst
the route servers.
The direct peering between the PEs is done within the vrfs - ie each
PE has a loopback in a vrf Internet and the ibgp sessions directly on
those loopbacks. Those sessions only exchange the 'internet' prefixes
and export default into other vrf, so basically it works like if they
were completly independed routers.

kind regards
Pshem