Re: 56K Modems - Do I really want mine?

dtrucken@zsassociates.com
Thu, 21 Aug 1997 13:31:34 -0500

>>
>> Is there any word about the seemingly broken V.42 implementations that
hang
>> up after 12 resyncs? Is this a Livingston problem or a problem with all
>> (or most) modems?
>
>That's not a bug! The end which rejects six packets (requesting
>retransmission) is supposed to ask for a retrain and/or renegotiation
after
>the six. If you get to *12* and haven't renegotiated the connection, you
>get dropped. This is what is *supposed* to happen.
>
>What's happening is that some modems don't request the renegotiation after
>the errors occur. Thus, the count piles up, and eventually the Lucent
>chipsets hang up with a V.42 retry limit exceeded error. This is *proper*
>behavior.

Ah, that explains it. Not a bug, but an unintended functionality. Well we
can't really blame a company for following the spec's. Of course, I seem
to remember that TCP/IP stacks are full of these kinds of "fixes" so that
"broken" implementations will work. Seems that modem code will soon be (or
already is) full of the some kind of junk in the name of inter-vendor
functionality. Glad to hear that Lucent is working on a fix, I can't
wait...

>> Is
>> error control and modem compression really not necessary since I'm using
>> PPP and PPP compression (what ever that is) anyway? What do people
think?
>
>If you have STAC cards in the box, you can shut off error control entirely
>and use PPP's error control for this (it works), and MS Windows
compression
>(check the "software compression" box in the profile) for compression.
This
>is a STAC derivitive.
>
>That's a *very* viable solution to the problem.

Cool, this sounds very promising, I'll call my Livingston rep and order me
a card.

Thanks Karl for the information, you are a wealth of help.

Dave Truckenmiller
dtrucken@zsassociates.com