Re: PM3 digital modems SLOWER than analog?

Evan Champion (evanc@synapse.net)
Tue, 08 Apr 1997 12:42:44 -0400

Jaime Bozza wrote:

> I'm just hoping the new modem code is soon. If that fixes the latency
> issues, and the transfer speed issues, I'll be happy. As for the 14.4K
> problems, we only have a single customer so far. If we start to have more
> problems, this will also become something that (I feel) should be
> resolved.

The only real problem we are seeing is with ISDN uploads. Downloads go
at full rate (say, 11 K/s to a Bitsurfr Pro doing Multilink), but
uploads go at under half that. We did some poking around and found that
for the platforms where this is a problem (the latest RedHat is one of
them), setting the client's MTU to 576 instead of 1500 resolved the
problem. We'd still like to find out why this is a problem, and is it a
problem on the PM3 or with the client. This doesn't seem to happen with
analog modems; our theory is that the higher speed/lower latency of ISDN
is just exacerbating a problem that is also there with analog modems.

Evan