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Re: DARPA get's it right this time, takes aim at IT sacred cows

2004-03-14 09:52:46


While in general I agree with what Scott Michel there is one point of controversy no-so-hidden in his message:

Scott Michel wrote:

The article also mentioned something along the lines of "Redesign The
Seven Layer Model!" Frankly, I've always preferred the four layer IETF
model because it didn't have the extra useless layers; but hindsight is
20/20, after all. I could look at the ceiling and foresee the session
and presentation layers suffering the death they truly deserve, but
the remaining layers staying intact. Layers may need subdividing or even
outright addition to the current model so that overlays and the recovery
semantics they provide are more explicit.

I agree.  The subdividing has begun.

Say what you will, but in large portions of the Internet we are no longer a four layer stack. Between VLANs, IPsec VPNs, and MPLS, we've inserted a few more layers. It goes back to Steve Deering's hourglass presentation. We can argue over their usefulness.

While I've not been witness to an argument about the usefulness of the presentation layer, I have been witness to huge arguments over the session layer that go on to this day. Arguably we have some advances to make, and the existence of a HIP working group seems to indicate the usefulness of something above Internet and below transport, while the ADD-IP improvements in SCTP in an odd way validate some of what those session layer folk were going for. Perhaps with ADD-IP we have what amounts to a "pseudo-session-layer".

Anyway, bar room talk for San Diego.  I hope to see you there.

Eliot