Path: utzoo!attcan!uunet!lts!amanda
From: amanda@lts.UUCP (Amanda Walker)
Newsgroups: comp.dcom.modems
Subject: Re: V.32 will dominate the marketplace (Was: Re: Which is best?)
Message-ID: <721@lts.UUCP>
Date: 14 Nov 88 15:04:30 GMT
References: <2261@looking.UUCP> <1248@nusdhub.UUCP> <14515@mimsy.UUCP> <14533@mimsy.UUCP>
Distribution: na
Organization: InterCon Corporation, Reston, VA
Lines: 65

In article <14533@mimsy.UUCP>, chris@mimsy.UUCP (Chris Torek) writes:
> [stuff about TB+]
> ... to be on the order of ten milliseconds.  This could be fixed by having
> the tty driver speak a protocol with the modem, so that the modem
> knows when to send immediately and when to wait.  (This is, of course,
> the moral equivalent of spoofing.)
> -- 
> In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
> Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris

Thins brings up an interesting point.  There seems to be some
disagreement about the "moral value" :-) of protocol spoofing.  Some
people think it's the best thing since invention of the modem.  Some
people think it's a grody hack that allows modem companies to squeeze
money out of unsuspecting customers (this is simplified, but seems to
be the gist of it).

It seems to come down to the fact that different people see the
concept of "what a modem should do" differently.

There are those that think a pair of modem should be a "virtual wire;"
they tend to like full-time full-duplex schemes like V.32.  The only
problem is that, at least for a while yet, the phone connection
*between* the modems isn't much like a virtual wire, and things that
work well over a few hundred feet of copper don't work so well over
couple of satellite hops.  Even so, this approach does let them work,
if poorly--most computers know how to talk to a wire, after all. 

There are those that think a pair of modems should be pair of experts
on how to get bits from point A to point B.  Now, there isn't (that I
know of) any standard "smart communications controller protocol," but
protocol spoofing isn't too bad of an approximation.   Any protocol
imposes a structure on the data, which the modem can then use to get
better performance than it could if it had to pretend to be one end of
a wire.  Thanks to the multiplicity of protocols, this does make life
interesting for the engineers at places like Telebit.  However, if
they cover the most common ones (at least, the most common ones for
the markets they want to tackle), then a large number of people can
benefit.

I take position number two, if you couldn't guess :-).

One thing that I would love to see in a modem, whether the underlying
technology is a full-duplex scheme like V.32 or a fast half-duplex
scheme like PEP is to be able to tell the modem what you want.  Right
now the protocol spoofing in a TB+ infers this from the protocol you
are using.  What I'd like to see is the ability to say someething like
"OK, I want this fraction of the channel for this direction, and this
fraction for the other direction."  It's not as good as understanding
the protocol, but it's better than trying to be a wire.  For example,
this would make things like SLIP (that fall just off the edge of the TB+'
s interactive mode) much happier, and would in general make the modems
more useful to people who aren't using supported protocols.

It's sort of like a group of people working on a project: the more
they tell each other what they are doing and what they need, the more
smoothly things tend to go...

Comments?

-- 
Amanda Walker
InterCon Corporation, 11732 Bowman Green Drive, Reston, VA 22090

...!uunet!lts!amanda / lts!amanda@uunet.uu.net