Re: [ECOS] PPP/GPRS problems

[Nick Garnett <nickg at ecoscentric dot com>]

"Deak, Ferenc" <feco@stp.hu> writes:

> Hello,
> 
> I'm trying to create a PPP connecton with a GPRS modem. During
> cyg_ppp_wait_up I'm getting random messages something like
> 
> ppp0: bad fcs 95fa, pkt len 25
> ppp0: bad fcs d70a, pkt len 20
> ppp0: no compressor for [15 3 29], 3
> ppp0: no compressor for [1a 4 8], 4
> ppp0: no compressor for [18 4 8], 4
> ppp0: bad protocol 600
> 
> (if I remember correctly sometimes there is no "bad protocol" or "no
> compressor" messages only "bad fcs") But after it, the server assigns an
> IP address to the device, which I can see in the routing tables and in
> the interface statistics. But after this I'm getting only error messages
> something like: "ppp0: bad fcs 5049, pkt len 33", when I'm trying to
> connect to a host.
> 
> The device has no hardware flow control lines. Is there anybody who can
> assure me, that PPP have to work without hardware flow control?
> 
> I've tested the modem under linux, with flow control, without flow control, and
> xonxoff settings, and it was good with every setup...
> 
> The version of Ecos is almost the latest CVS.
> 

PPP will certainly work without hardware flow control, but only if you
enable software flow control. It really needs flow control of some
sort to work, but that obviously depends on the modem being capable of
being configured to use software flow control too.

You might also try reducing the baud rate and see if that makes a
difference.

It may also be worth testing eCos against a Linux host and see whether
you get the same behaviour.

All of this should give you some ideas about where things are going
wrong.

-- 
Nick Garnett                                     eCos Kernel Architect
http://www.ecoscentric.com                The eCos and RedBoot experts


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