Re: 2 cents re: MTU

Brian Godette (
Thu, 25 Jun 1998 16:37:59 -0600

At 02:57 PM 6/25/98 -0400, Bernard Matthews wrote:
>Hi Brian,
>Are the rules changing because of the overall speed of the
>connections/technologies involved, or because of the asymetry
>of these higher speed technologies between the user and the ISP?

For the "56k" modems the ISP->client latency is nearly the same as ISDN as
there's no encoding/decoding of the signal, it's assumed to be a digital
circuit (visit for a better description of how it all works),
the latency being right around 30-40ms. Upstream is still slow at around
120ms as it's still using analog. And of course the higher speeds effect it
as well, given an average (at least out here) sustained DCE rate of 46000
brings the transfer time down to ~260ms for a 1500 byte packet. As for
asymetry, most 28.8/33.6 analog connections are asymetric, but since
connect rate reporting only shows the rate from the other end to you, most
people don't realize this.

>Just curious, and possibly off topic.
>----- bernard