[68661] in North American Network Operators' Group
Re: iMPLS benefit
daemon@ATHENA.MIT.EDU (W. Mark Townsley)
Mon Mar 15 14:35:01 2004
Date: Mon, 15 Mar 2004 20:30:39 +0100
From: "W. Mark Townsley" <townsley@cisco.com>
To: Yakov Rekhter <yakov@juniper.net>
Cc: David Meyer <dmm@1-4-5.net>, sonet twister <sonet1010@yahoo.com>,
nanog@merit.edu
In-Reply-To: <200403151826.i2FIQdJ71490@merlot.juniper.net>
Errors-To: owner-nanog-outgoing@merit.edu
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
