Modem Negotiated Speed
Russell King (rmk@arm.uk.linux.org)
Thu, 16 Jul 1998 21:39:42 +0200
Gert Doering writes:
> > I know this has been talked about before, but for the life of me I
> > can't find what the answer was for it. I have to have what speed the
> > modems have negotiated during connection. I desperately need this as
> > to monitor and plot dialin loads on the server, verses modem speeds.
> > It is one of those Research and Development variables that are a *must
> > have*.
>
> ... which is why it's there, since about 2-3 years now :-)
I'm sorry, but I don't really see the purpose of logging the speed at all.
Yes, I agree that there should be some way of calculating the server loads
vs modem speeds, but the negociated speed is not representitive of the
speed throughout the whole call.
Generally, if you have a really good line, you'll get about 56k through it.
However, when you start to get noise, it's amazing what happens. You find
that the modem initially connects at, say, 33k6, and within the space of a
few minutes it's dropped to 28k8 or 26k4. Hence the figure that you got
is no longer true.
Ok, so how do I know this? I have one of those modems that tells me on the
front panel what speed it is currently using. I bet that a lot of people
would be supprised by how much the modem speed changes during the duration
of a call on a slightly noisy line.
The only time that I can see that it would be useful is if you turned off
auto-fallforward/fallback. That way you know that the speed that you
connected at is the speed that the modem link will use for the duration
of that call.
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