iMPLS benefit

Mon Mar 15 19:30:39 UTC 2004

Yakov Rekhter wrote:

> No, I was *not* referring to draft-raggarwa-ppvpn-tunnel-encap-sig-03.txt.
> Redback's implementation that does not require manual provisioning of 
> point-to-point GRE tunnels between MPLS networks and to each and every 
> IP-only reachable PE is *purely* an implementation matter, and does *not*
> require any new communities and/or attributes.

OK, you made me go out to www.redback.com and read about their implementation.

A quote:

"This means that the ingress router can learn these next-hop addresses through 
MP-BGP, and then dynamically append the GRE encapsulation and outer IP header to 
a VPN packet destined for an egress router. In essence, these GRE tunnels can be 
considered as “soft” or dynamic because they do not need to be configured. "

Whether it is implicit from the next-hop address in BGP, or explicit in the 
next-hop update via draft-nalawade-kapoor-tunnel-safi-01.txt or 
draft-raggarwa-ppvpn-tunnel-encap-sig-03.txt, we are still talking about MP-BGP 
as the vehicle for advertising how to reach a PE by GRE. We now have identified 
three variants for MPLS over GRE in this thread, (outside of manually configured 
"hard" GRE tunnels) -- back to my original point that "MPLS over GRE" can mean a 
lot of things.

IMHO, a PE explicitly identifying that it can receive MPLS over GRE (or MPLS 
over foo) traffic is a bit safer and more deterministic than implicitly assuming 
it can from a learned next-hop address. I don't want to speak for another 
company, but perhaps Redback did too which is why they helped sponser 
draft-raggarwa-ppvpn-tunnel-encap-sig-03.txt in the first place. Go knock on 
Rahul's cube now that the two of you work at the same company and ask him ;-)

- Mark