On 31 May 2006 15:13:02 -0400, "Nathan J. Williams"
<nathanw@wasabisystems.com> wrote:

> "Steven M. Bellovin" <smb@cs.columbia.edu> writes:
> 
> > I run ppp on an EVDO wireless card.  The PCMCIA card itself appears as
> > ucom0 on umodem0 on a USB hub at cardbus0.  The problem is that it isn't
> > as fast as it should be.
> > 
> > I've run the same web-based speed testers when running both NetBSD and
> > Windows.  On NetBSD, I never see more than 220K bps; on Windows, I can get
> > 650K-850K bps.  The question is what I should change.  MTU is 1500; I see
> > nothing else obvious.
> 
> Can you try cranking up these constants in umodem_common.c?
> 
> /*
>  * These are the maximum number of bytes transferred per frame.
>  * If some really high speed devices should use this driver they
>  * may need to be increased, but this is good enough for normal modems.
>  */
> #define UMODEMIBUFSIZE 64
> #define UMODEMOBUFSIZE 256
> 
Changing those numbers somewhat helped a lot.  I'm going to bump them some
more and try some tests when I'm not in a moving train.  (Well,
quasi-moving train; today isn't Amtrak's best day...)


		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb