On Sun, 7 Apr 2002, John Klos wrote:

> > Next question. To get the most out of my connection under windows 98
> > I had to tune tcp receive window (RWIN) and MTU. I can set MTU in the
> > ifconfig.sn0, but how can I effect the receive window of the sn0
> > interface to maximize my transmission speeds?
>
> Adjusting the MTU on a 10-base-T network used for Internet access? I'd
> never even considered such a thing. How fast is your line?
>
> Someone else will have to answer this for you - I've never run a Quadra on
> an Internet line that needs more than the 600k/sec that the NuBus ethernet
> cards generally do.

It looks like (for the client computers) the tcp stream gets its
characteristics from the client tcp/ip settings. I guess that
makes sense since the NetBSD box is just fowarding what
the client sends. (?)

With the cable modem, a RWIN of say 6400 might generate download
speeds of 600-1000 kbps. Setting the RWIN to ~64000 gets this
up to about 3000 kbps download.

I was not successfull changing MTU with the ifconfig.sn0. I got
some wierd message:
sn0ifconfig: SIOSIFMTU: Invalid argument

My ifconfig.sn0 (which later get configured with DHCP):
mtu 1492
[hmmm, on re-reading the man page, it says "most interfaces
don't support this option! 8-0 ]

I have configured all my clients to get ~3000 kbps down, so
being able to tune sn0 on my NetBSD box will really
only help downloads originating from that box...
I probably won't be using that box too much directly,
but it'd be nice to know.

Thanks again John! UdaMan!
--gene