Telecom-REQUEST@MIT-XX.ARPA (Moderator) (09/03/85)
TELECOM Digest Monday, September 2, 1985 6:52PM
Volume 5, Issue 31
Today's Topics:
X.PC protocol description available
PC Pursuit (with opinion section)
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Date: Sun, 1 Sep 1985 09:57 MDT
From: Keith Petersen <W8SDZ@SIMTEL20.ARPA>
Subject: X.PC protocol description available
Now available via anonymous FTP from SIMTEL20:
Filename Type Bytes CRC
Directory MICRO:<CPM.MODEM>
X-PC.DOC.1 ASCII 127850 34DFH
X-PC.DQC.2 BINARY 77056 CA2CH <-same, squeezed
[Keith: which MAY be the same as TYMNET offers as:]
Now available from your local Tymnet sales representative:
X.PC PROTOCOL SPECIFICATIONS NPD-269 $3.00
This specification is published by McDonnell Douglas as a proposal to
designers and implementors of personal computer communications
software and packet network systems.
It defines the formats and procedures at X.PC's packet and data line
layers for Data Terminal Equipment (DTE) and Data Communications
Equipment (DCE). Both switched virtual call and permanent virtualy
call modes of operation are defined.
This specification covers DTE and DCE operation when a packet switched
network is accessed through a circuit switched or dedicated
connection. It also includes the additional packet layer procedures
necessary for two DTEs to communicate directly (i.e., without an
intervening packet switched network) over dedicated or circuit
switched connection.
[Keith: this is the much-talked-about "error-free terminal protocol"
now supported by TYMNET. It is an interesting alternative to
MICROCOM's "MNP" protocol which you must buy a new modem to get (and
which requires the "other end" to also have this type modem). If we
could get BBN to support the X.PC protocol in the TAC software, we
could have error-free sessions in spite of occasional noise on the
phone lines.]
--Keith
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Date: Sun, 1-Sep-85 17:03:54 PDT
From: vortex!lauren@rand-unix.ARPA (Lauren Weinstein)
Subject: PC Pursuit (with opinion section)
This is a repeat posting to some lists by popular demand. Apparently
there were some delivery problems with the original. Please excuse
if this is a duplicate for you...
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From: Lauren
Subject: Re: PC Pursuit (plus opinions)
Some tests someone ran locally with PC Pursuit failed
dismally. Terrible throughput at anything faster than 300 bps. There
still seems to be extreme variability from place to place.
Also, I was told (off the record) that the implementation of non-local-
calling blocking would take place "as soon as they could get accurate
prefix info for their tables" to block out most prefixes. They also
mentioned that they might be asking for certification that the
service is not being used by commercial firms but only by
individuals, since they don't want commercial traffic people tying
things up. The thing they DON'T want is people tying up the dialers
with call after call. Another possibility mentioned was a "cap"
on the amount of time the service could be used in any one 24 hour period,
so "everyone would be able to get some time." A one or two hour limit
was mentioned. Anyway, all of this was off the record. Take with
as many grains of salt as you wish.
----
Opinion section starts here:
If you analyze this service, it's pretty clear what's going on.
GTE is attempting to maximize use of facilities already in place
that tend to sit idle outside the business day. Those facilities
are not massive (24 dialers for all of Los Angeles, for example).
It seems unclear how they can EXPAND beyond the current levels based
on the $25 flat rate fee, since local telephone lines and dialers
are going to be one of the most expensive recurring costs in the
operation. It's also pretty obvious why they are concerned about
making non-local calls. Take a call from L.A. Central (where TELENET
has their node) to Santa Monica. This is a very modest ZUM call (there
are MUCH more expensive calls possible within the tiny 213 area code).
Even so, that call (evening rate, night is a little cheaper) is 10 cents
for the first minute and $.05 for each additional. So a one hour
call (either on the originating or terminating end of the call) is
going to cost them something like $3.00/hour. Figure that (until
blocking is in place) many calls are of this sort, and you might
find that $6.00/hour (considering both ends) will be the minimum cost
of such calls (ignoring equipment and other costs at this point).
If you make FIVE one-hour calls of this sort during evening hours
during the month, you've already cost them more than the price
of the service! It takes a few more hours (or slightly more
expensive non-local calls) to reach that level at late night-rate, but
you can still reach the "no-profit" point for them damn fast.
Hell, businesses in most areas pay about $.60/hour even for LOCAL
calls--never mind the toll and ZUM charges! All of this cuts
into GTE's profit margin on such a service. Even if GTE opens
the service up to other metro areas, the fundamental economics
don't change.
So, what will occur? Let's ignore service quality issues (throughput,
dialer congestion, insufficient ports, etc.) for the moment. The
sheer economics of the phone charges will either force the blockage
of many non-local calls (which will make the service much less
generally usable) or force restructuring of the service. Either
prices will change, or service limitations will be set in place,
or... something else will have to give. A couple of hundred
BBS fanatics in each of the 12 metro areas could totally tie up
the service in nothing flat. Once again, I'm only considering port
and dialer congestion, not the overall impact on TELENET throughput
of all these people.
One can't help but suspect that GTE is already very aware of the
changes that will have to occur. One might suspect that what they're
trying to do is get people signed up now--and then announce whatever
changes (in pricing, type of service, etc.) that they want down
the line. I guess there's nothing terribly wrong with doing that--but
I think people are being a little naive is they think that such
a service can continue in its currently announced form and at
currently announced prices indefinitely! I fully expect to see
changes--or else the congestion and other factors will simply
make the service unusable except for BBS crazies who don't
have to worry about having anything important going wrong if they
can't get through much of the time...
--Lauren--
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Date: Sun, 1 Sep 85 19:10:38 edt
From: <ihnp4!watmath!looking!brad@Berkeley>
To: watmath!ucbvax!Telecom@MIT-XX.ARPA
Subject: Listening in to signals
Newsgroups: fa.telecom
In-Reply-To: <8509010526.AA18383@UCB-VAX.ARPA>
References:
Cc:
Bcc:
While I agree with many that you can't and shouldnt make laws
banning receivers, I am often amazed at the attitude that a consequence
of this is that it's OK to steal HBO.
One shouldn't make a law banning the ownership of baseball bats, but
that doesn't make it morally right to club somebody with one.
How often have I heard, "they're beaming that signal through my house, I
have a right to watch it." Where is the justification for this?
With sensative microphones, you can listen to your neighbour's conversations
because their voices are broadcast through the air. To do this would
be wrong, however. You can listen to people talking on cordless phones,
but it's certainly not something people should do. Is there no courtesy
in the world?
The fact that something is broadcast rather than point to point has
nothing to do with it. These signals are private communications between
the broadcasters and their customers. They have repeatedly requested that
you respect that privacy and not watch. Yet people buy special equipment
and go to great lengths to do exactly that. If you set up a telescope to
look in your neighbour's window you would be a peeping tom. If you looked
into a corporations boardroom where they didn't draw the drapes, you would
be an industrial spy.
If I "broadcast" something in a way that you have to go to special lengths
to listen to it, and I ask you not to do so, then I don't think you can
say what you're doing is right.
Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473
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End of TELECOM Digest
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