[c-nsp] vrf-lite over a layer3 link

Roman A. Nozdrin drrtuy at ya.ru
Tue Oct 6 08:42:18 EDT 2009


> This is my first post to this list, so I guess I should say hello ;-)
> We are considering an advanced network design which allows us to separate
> several services or customers using vrf-lite. There are some local sites
> which are connected by our own cabling. Nevertheless there are also some
> remote sites which are connected over a provider which provides common
> layer3 links. I understand that vrf-lite uses vlan's to separate the
> customers between ce and pe, I have seen these in all the examples I already
> read. As supposely no provider supports vlan's but rather layer 3 lines the
> big question is: How to span a network using vrf-lite over a provider?

In this particular situation I would prefer tunnelling technologies to 
tie remote POPs. You can put tunnels into different vrfs and forward 
VRFs' traffic through respective tunnel next hop using static or dynamic 
If the ISP can route Your customers prefixes You can also take a 
difficult way. Your networks edge router can merge all the customers' 
routes before the ISP segment using route leaking feature. The other 
edge router will redistribute the routes back to VRFs using the same 

Roman A. Nozdrin

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