Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!guy
From: guy@sun.uucp (Guy Harris)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: What is SLIP?
Message-ID: <41751@sun.uucp>
Date: 12 Feb 88 06:30:10 GMT
References: <325089.880211.JBVB@AI.AI.MIT.EDU>
Organization: Sun Microsystems, Inc. - Mtn View, CA
Lines: 37

> I have been told that SLIP has its roots in an old serial protocol 3Com
> came up with for communicating between fileservers, and was adopted for
> use with IP and asynchronous serial lines some time later, initially for
> use between gateways (IP routers).  Rick Adams did a public domain
> implementation for 4.2 Unix, and now one is distributed with 4.3.

The history, as I understand it (the CCI parts are correct - I was there - but
I don't know the history of this encapsulation scheme at 3Com):

	3Com's UNET TCP/IP implementation had a serial line encapsulation
	for IP packets.  I don't know for what this encapsulation was
	originally designed, but it was used in UNET for getting two machines
	with serial port hardware and nothing else to talk IP to each other;
	it was not just used between gateways.

	The Naval Surface Weapons Center put out a bid for an office
	automation system; Computer Consoles, Inc. bid a system consisting of
	two VAXes running 4.2BSD (with S5 compatibility additions) and lots of
	CCI Power 5/20 machines running S3 with UNET.  There needed to be
	*some* way to get the 5/20s to talk to the VAXes, so Rick whipped up
	the original SLIP; it used the 3Com encapsulation so it could talk to
	the 5/20s running UNET.

	He subsequently reimplemented it while at the Center for Seismic
	studies.

> I have heard that Sun will support it soon, if not already,

We don't have it now; I don't expect it to be officially supported in the next
release, but Rick does have a version that can, I believe, be put into current
SunOS releases, and I expect there will be versions to put into future
releases.  It may end up in a future release, but I don't know one way or the
other.
-- 
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com (or guy@sun.arpa)