Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!GATEWAY.MITRE.ORG!barns
From: barns@GATEWAY.MITRE.ORG (Bill Barns)
Newsgroups: comp.protocols.iso
Subject: Re: OSI IP routing on the DDN?
Message-ID: <8904281656.AA05456@gateway.mitre.org>
Date: 28 Apr 89 16:56:05 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 17

My highly esteemed senior colleague Paul Tsuchiya points out that I
improperly painted with too broad a brush in the last sentence of my
previous reply when I said:

> [...] distinct values are used to distinguish the next higher layer
> as IP, CLNP, ARP, ES-IS, or whatever.

I SHOULD have said "IP, ARP, OSI, or whatever."  The difference between
the two is small but quite significant.  You disambiguate OSI network
layer things from non-OSI network layer things at the lower layer or
fraction of a layer (although you may be able to fake it for now from
the first octet).  You disambiguate between various OSI network layer
things such as CLNP and ES-IS within the OSI network layer, using the
protocol identification there.  To be completely general, it is
necessary to play both of these games correctly.

Bill Barns / MITRE-Washington / barns@gateway.mitre.org