Path: utzoo!utgpu!attcan!uunet!ncrlnk!ncr-sd!hp-sdd!ucsdhub!jack!nusdhub!rwhite
From: rwhite@nusdhub.UUCP (Robert C. White Jr.)
Newsgroups: comp.dcom.modems
Subject: Re: V.32 will dominate the marketplace (Was: Re: Which is best?)
Message-ID: <1245@nusdhub.UUCP>
Date: 10 Nov 88 05:38:21 GMT
References: <407@telly.UUCP>
Organization: National University, San Diego
Lines: 87

in article <407@telly.UUCP>, evan@telly.UUCP (Evan Leibovitch) says:
> The jury is still out on whether these yet-non-existant cheap V.32 modems
> will have superior specs to the 'Blazer. How can you be so cocky touting
> the merits of modems which nobody has seen?
> 
> Telebits let me talk to the sites I need to talk to at high speeds.
> Tell me how V.32 will change that for the better.
> Where is the V.32 superior technology?

Having seen/dealt with the V.32 modem at this years TCA convention
(which was held in San Diego last month or so)  I will now degin to
discorse (;-) what the V.32 technology will get you over the
Trailblaizer Technology (and vice versa.)

V.32 is real(tm) full-time-full-duplex while the PEP system is
"negotiated" (my word) full-duplex.  In order to get the full 19.2
capacity of a PEP modem you must be able to drop full >3K data streams
into the modem all at one time.  If you do not drop these huge packets
into the modem (or stream many small packets through a large verify
window) you will pay turnaround penalities for each packet.  To
address this, Trailblaizer et. al. started something called
protocol-spoofing (most of you know this, but that is for those who
didn't).  By spoofing a protocol, the modem at each end pretends that
it is the distant computer (as far as the protocol is concerned) and
simply varifies each packet, and then loads up its own buffer with the
data and transmits it using its own protocol.  Both ends of the line
preform in the same manner.  Without spoofing, you might as well have
a 1200 (your mileage may vary ;-) baud modem for small packet
protocols.

Spoofing has several major drawbacks to PEP.
	1)  Both modems must be programmed to spoof the desired
		protocol.  This implies that "new protocol => new ROM"
		which can cost you big time, or not be available.
	2)  Complex pick-up-where-you-left-off type protocols may fail
		(depending on the spoofing implementation) completely
		around connect interrupts because computer A knows
		that packet 2346 got through while computer B never
		even got 2331, so second call recovery will have a
		bitch of a time re-sync(ing).
	3)  Because of point 1, the modem's longevity is tied directly
		to the manufacturers support and longevity.

Why the same draw-backs do not apply to V.32.
	1)  V.32 is full-time-full-duplex.  The same preformance is
		provided to transporting 1 character as 1,000,000
		(per capita)
	2)  Point 1 makes any protocol concerns (as far as the modem
		is concerned) moot.  e.g.  if your software will do
		it your modem will do it.
	3)  V.32 contains satalight silencing and crosstalk
		compensation consistent with international standards.
	4)  V.32 modems are "transparent, non-intrusive" carriers so
		they will not interfere with real-time opperations.
		(encoding and such)


NONE of these points will bother any installed base of PEP modems, but
the installed base of PEP modems will have its growth stunted.  Many
large institutions have avioded PEP modems and simply waited for V.32.
(Yes, like us, the third largest private instutition of higher
learning in the state of california).  PEP 19.2 vs V.32 9600 only
apears to be a 2-to-1 speed difference, agregate throughput discounts
the PEP substancially (for many applications I can think of) towards
V.32.

Since V.32 does not lock us into any one company or into current
technology.

If you look to the immeadite future, you will see the re-working of
many protocols threatening your horizions.  (see "tar wars" and uucp
"e" protocol, and "dart," and "gossip," and ...)  You may see
(depending on who you are) that buying a PEP modem is buying into a
dead end street (now).  Your installed base may go beyond a "growth
slowdown" and start to actually shrivel up.  Can't you see the
promotions now. . . .

[  (in my best political/beer-comercial voice:
	"Turn in that old PEPless horse, and go with a *standard*,
		catch the (square) wave; V.32"]  ;-)


Disclaimer:  Ignore the typos and spelling errors;  I am being harried
	right now and this disclaimer is "more expedient" (faster?
	now where have I heard that before?) than a proofread.

Rob.