[Int-area] tunneling and recursion (was: Re: New Version Notification for draft-li-int-aggregation-00.txt)

[Toerless Eckert <[e-mail]>]

On Fri, Feb 25, 2022 at 08:19:42PM -0800, [e-mail] wrote:
> I disagree; a tunnel (done correctly) is isomorphic to a link. There’s no difference between tunnels and what we already rely on as “L2”.

I guess wrt. routing we (Internet Routing Architecture) started out with
alot of simplifying assumptions about the properties of links. Primarily them
being full-mesh-mp2mp or p2p. And then MPLS gave us arbitrary mesh mp2p LSPs,
 and then MANET came with arbitrary partial-connectivity meshes. I don't this
we ever formalized any of this so that we could really confidently use 
link or tunnels and be clear about what options the reader will assume.

> The flaw is the OSI model assuming layer levels are absolute (they’re relative) from all viewpoints (again, relative). There’s a strong equivalence between a link, a tunnel, and a router (which, in essence, emulates shared link). And, interestingly, forwarding can also be described as recursive tunneling.

I thought you just look whats on the wire and you know
the level. If its a frame it's L2, if it's a packet, it's L3. If it's
anything more complicated, it's a tunnel (sorry, couldn't resist ;-))

Is there any IETF RFC that is actually any better than OSI in this respect ?

And yes. I wish there was better material about recursion as the core
fundamental of building networks. Especially because so far we mostly
have re-invented the wheel for every instance of recursion (frame,
packets, tunnel headers..).

Cheers
    Toerless