Re: novatel minstrel on 2.4

Joe deBlaquiere (jadb@redhat.com)
Thu, 01 Feb 2001 21:25:36 -0600


Adam Fritzler wrote:

> We've been trying to set up a laptop here to use a Novatel Minstrel PCMCIA
> modem (wireless Richocet network). The card shows up as a serial port
> (ttySx) and accepts AT commands just like a normal modem.
>

I'm in the process of bringing up a Novatel Merlin now (tomorrow morning
actually). I don't know how similar it is, but they do at least use some
common hardware on the Merlin and Sage products.

> It dials fine, PPP connects, gets IPs, etc just as it should. However,
> any packet over about 400 bytes gets dropped on the recieve. Also, the RX
> errors on ppp0 increment occasionally.
>

According to http://people.freebsd.org/~nsayer/ you have to set the mru
to 576 for the Merlin. There is some fairly detailed info on
http://www.mrollins.com/newtmerlin.html about setting it up for (of all
things) a Newton including all the expected commands which implies that
you should adjust the mru setting on the card and then match that with ppp.

> TCP connections connect (because the SYN's are small), but as soon as you
> start trying to do bulk transfers (`ls -la` in an ssh window, or an HTTP
> GET), the connection stalls. Pinging other hosts also works fine, except
> when you do -s with a value larger than 300 or so.
>
> It doesn't work with anything we've tried on 2.4 (changing mtu/mru, serial
> port speed, etc). However, under 2.2.x, we were able to get connections to
> stay running and not stall by setting the MTU on ppp0 to 120 after the ppp
> comes up. As you can imagine, this makes the modem seem even slower than
> it already is.
>
> Not that its relevent, but pppstats shows 0 in the 'vjcomp' fields of
> both rx and tx (as well as 'vjerr'). I've tried starting pppd with and
> without 'novj' just in case. Same result.
>
> Any ideas? The 'rx error' count going up is kind of suspicious. My
> attempts at getting pppd to print more debugging output have been
> futile; aparently the debug and kdebug options no longer work ('debug'
> produces the LCP traffic, yes, but thats working fine).
>
> af
>
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-- 
Joe deBlaquiere
Red Hat, Inc.
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