Path: utzoo!utgpu!water!watmath!looking!brad
From: brad@looking.UUCP (Brad Templeton)
Newsgroups: comp.dcom.modems
Subject: What the world needs is a protocol for high-speed, error free modems
Message-ID: <1576@looking.UUCP>
Date: 25 Apr 88 18:18:24 GMT
Organization: Looking Glass Software, Waterloo Ont.
Lines: 41

Now that I've got a telebit, I'm actually noticing more waste in my
telecommunications.

With the speed and error correcting nature of these and other modems, such
as 9600 baud MNP modems, using the various protocols we've got with short
packets and lots of backtalk, along with slow handshaking.

If I watch a uucp mail transfer at 19200 with my telebit, at least half
the time, if not more, is spent doing nothing while the UUCPs figure out
what file to send next and handshake about it.  Data flows the other half
of the time if you're lucky.

The other wastage is machines that can't take input data at 19200, and
even those who can't send it.  I get the full 1400 or 1500 bytes/second
when the vax I talk to is unloaded, but it drops a lot during the day.

What we need is a protocol that:

	a) Bunches up all the files before initiating the call, so it's
	   just a constant data stream

	b) Uses big fat packets, 10K or 20K in size.
		(or uses a packet time in seconds rather than bytes, ie
		"5 seconds" means 150 bytes at 300 baud and ~5K at 9600 baud.)

	c) Does minimal error checking, ie. one CRC per 10K packet.

	d) Can use a restricted character set so that more efficient
	   'line at a time' tty driver modes can be used, and also so
	   that LANS and packet switch nets don't interfere.

	e) Possibly uses shorter packets but doesn't actually wait for the
	   ACK before sending the next packet, but rather sits and examines
	   any NAKs that come or ACKS that don't, and resends those packets.

Anybody doing anything like this?  In theory it should be a lot simpler than
the protocols that had to handle high-error lines.

This would also be useful over dedicated serial links, for example.
-- 
Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473