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From: mccallum@opus.UUCP
Newsgroups: net.lan
Subject: Re: ISO Protocol Suite
Message-ID: <289@opus.UUCP>
Date: Wed, 28-Mar-84 12:21:23 EST
Article-I.D.: opus.289
Posted: Wed Mar 28 12:21:23 1984
Date-Received: Fri, 30-Mar-84 02:42:46 EST
References: <1158@cbosgd.UUCP>
Organization: NBI, Boulder
Lines: 44

The ISO suite is getting close.  NBS is specifying the US version and is
developing a test bed for the protocols.  The transport layer is in draft
stage and several implementations exist.  NBS has one that is available
as part of the transport testbed.  It was done at BBN for NBS and is written
in C.  The transport is going to be demoed at this years NCC by a number
of vendors.  This demo is being organized by NBS.  There will actually be
two booths - a CSMA/CD (IEEE 802.3) and a token bus (IEEE 802.4).  The 
vendors also include at least one European vendor. (a version of the
transport protocol was published as an ARPA RFC [RFC892]).

The NBS transport testbed is up and running.  An article about it appears in
the March 84 issue of Data Communications.  A fairly complete set of tests
exists.  I've seen the testbed in operation.
  
The ISO session layer is in draft stage as well as the IP protocol.  A
followup demo of with the internet will probably be done if the NCC
demo goes well.  The NBS CBMS (Computer Based Messaging System) protocol
is now a FIPS (see FIPS pub 98 or RFC841)

I personally don't see any need for the restriction about keeping datagram
service separate from connection based service, but since it took a long
time to even get datagrams (unit data in NBS) it is probably
political.  There is a lot of resistance to datagrams in general.  
The 802 standards specify fully connected virtual circuits at the link
level.  Connectionless use is still available.

Addressing should be in draft proposal stage this month.
I'm not sure which addressing proposal is being adopted, but there have been
several proposed.  At one point NBS had an IP proposal with 64 bit addresses
(16 network id, 48 host id).  ECMA has proposed variable length addresses.
Given the comment about hierarchical addresses, I would assume that addresses
have a variable length with each part interpreted by the domain it references.

The ISO protocols have a lot of options.  A minimal subset should be fairly
small.  The NBS testbed runs on a PDP-11/70.  The code is in C but was 
generated by a protocol compiler that doesn't do any optimizations of the
finite state machine.  I think a subset could be implemented that would run
on a PC class machine.  There will most likely be a number of controllers
that implement the protocol directly.

			Doug McCallum
			NBI, Inc.
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