Path: utzoo!utgpu!watserv1!watmath!att!tut.cis.ohio-state.edu!ucbvax!star.enet.dec.com!mann
From: mann@star.enet.dec.com (Bruce Mann ZK1-3/J35 DTN 381-1298  21-Jan-1991 1257)
Newsgroups: comp.protocols.tcp-ip
Subject: TELNET versus LAT
Message-ID: <9101211758.AA24806@decpa.pa.dec.com>
Date: 21 Jan 91 17:58:54 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 37

>But could a protocol be designed that had the advantages of LAT
>(multiple streams in one packet, rate limiting, etc.) that ran over a
>network protocol (such as DECnet routing without NSP), or had adaptive
>timeouts?  

	Yes. The LAT protocol encompases a number of features, but the
session aggregation feature is independent of the LAT being built
directly on the datalink layer of Ethernet. 
 
>Indeed, despite implementation problems, in some ways CTERM (the
>DECnet virtual terminal protocol) is a better protocol, since it can
>dynamically switch between local and remote echo, even in a screen
>editor.  Of course, the application has to be well written to gain the
>advantages of the CTERM protocol.
 
	LAT makes no such effort at these optimizations. CTERM, TELNET,
and/or VTP could be run over LAT without modifications to LAT. In fact,
LAT is designed to be extensible to do this. Achieving these benefits
however (local echo for instance) often come at the expense of application 
transparency without sufficient compensation in the form of increased 
performance/efficiency.

>Unfortunately, with LAT proprietary, the standards bodies won't get to
>learn from it in designing future protocols.  It would be nice if the
>ISO virtual terminal protocols could have had some of these advantages.
 
	To my knowledge, all useful protocols start out being proprietary,
and evolve into "open" status as they become more widely used. LAT is
certainly in this transition now.

	By the way, while I do agree all protocols can be routed (layer 3),
I do not agree all protocols should be routed. The routing layer has 
obvious benefits, but also introduces some obvious problems. For example,
if every terminal should have its own IP address, why shouldn't every file ?
Where should the line be drawn ? 

								Bruce Mann