Date: Tue, 23 May 2006 20:15:35 +1000 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Mike Tancsa <mike@sentex.net> Cc: freebsd-net@freebsd.org, Brian Candler <B.Candler@pobox.com> Subject: Re: improving transport over lossy links ? Message-ID: <Pine.BSF.3.96.1060523200509.6317C-100000@gaia.nimnet.asn.au> In-Reply-To: <6.2.3.4.0.20060521154616.11bd1d60@64.7.153.2>
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Hi Mike,
On Sun, 21 May 2006 at 16:03:39 -0400, Mike Tancsa wrote:
> Correct. Its always dialing into a terminal server that is connected
> via PRIs. Usually Lucent PM3, sometimes Cisco 5800s depending on the
> location they dial from.
I guess you won't want to be messing with their configs, then ..
> > > The internal USR seems to correctly see the carrier drop and PPP
> > > hence sees it. However, the 2 external Intels I am experimenting
> > > with on the USB serial ports do not. I suspect thats part of the
> > > reason the DCD is not working. Perhaps incorrect init string or
> > > something with the USB-Serial. Note, I only have the internal USRs
> > > deployed in the field right now
> >
> >Don't know about USB modems. Do USR still use their own chipsets, or
> >what? In any case, they're probably highly tunable and well documented.
>
> Actually, they are just regular external modems connected to USB to
> serial adaptors (using the uftdi driver)
I had a browse through /sys/dev/usb/{uft,ucom}* but was well out of my
depth .. it =looks= like DCD (aka RLSD) changes should be picked up ok;
perhaps you're right about some odd init string or such - good luck!
> >Not V.90 full tilt, anyway. If 45333 is sort of usual for this one,
> >then I'd probably try telling it to connect no higher than maybe 41333
> >or 40000; often about 10-15% or so less than 'normal' can make all the
> >difference. If you can afford the bandwidth, go for slow and solid ..
>
>
> Yes, for sure I will try and lower the speeds a bit, but ultimately I
> want to deal with situations where the carrier drops and the modem
> has to redial. The client is willing to put in an extra phone line
> if it would make the link more reliable. Typically these sites are
> too remote for other types of transport. I think if I can get mp
> working with reliable dcd I think that should do it.
Fair enough. Chances of losing two lines at once are pretty small,
unless there are district-wide problems, given you get DCD going ..
cheers, Ian
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