The last time I used windows over a 56K modem (software type), I found
an even smaller MRU to be useful.� MTU doesn't have as much effect on
performance as MRU.� BAscially the scenario is this....
line error(rare) --> dropped frame --> discarded packet to be retransmitted
Software tied up(frequent)-->dropped frame-->discarded packet to be
retransmitted
So with 576 you lose less than with 1500 for retransmission.� I use 296
on Windoze for winmodems, 576 for hardware 56K modems.
On linux, with a slow modem, I use 296, 576 with a faster modem, and
1500 with a higher speed connection such as DSL.
I do note a few sites that freeze on MTU 1500 with modems and do not
with 1500 on DSL.� I puzzle at that behavior.� Packets do not carry
brand names or transmitting device types in them.� Perhaps the timing of
sending the longer packewt with a modem causes a problem on the transmit
end.
Civileme
Andrew Post wrote:
>
> I think that it's far from obvious that reducing the MTU really does
> improve performance. I have a 56K modem over a PPP connection (avg
> connection speed ~ 45K), and I didn't notice any performance change with
> an MTU of 576. I kept the change to 576 because I ran across a few buggy
> websites (www.adobe.com for example) that simply wouldn't load in Linux
> with an MTU of 1500, but would load with the lower MTU.
>
> Andrew
>
> vern wrote:
> >
> > I have wondered about the MTU value on
> > dialups, in windoze there is a big to do over
> > shorting your MTU from 1500 (default) to 576
> > for dialup networking. This is to reduce the
> > fragmenting of packets, errors, and retrys. I
> > have read no such concerns since being on
> > Linux it would seem that the same TCP/IP constraints
> > are there, can anyone enlighten this newbie??
> > Vern
> >
> > --
> >
> > ************************************************************************
> > * Vernon Stilwell [EMAIL PROTECTED], [EMAIL PROTECTED]
> > * R.R.#3 Box 168 [EMAIL PROTECTED], [EMAIL PROTECTED]
> > * Hardinsburg, Ky. 40143 "Happiness is a warm Penguin!"
> > * Registered User #165809
> > ************************************************************************
>
>
>
