pppd & gprs

Hello World,

I have written a client-application in C which runs as daemon and
talks to a server via TCP/IP.

My client is connected to the internet by a gprs-modem. Right now I
just start the modem and start pppd (with chat). After that I can
start the daemon which connects to the server. That is not a very good
solution, because a gprs and/or ppp connection can break :)

What is the best way to keep such a connection alive?
How can I determine from my C-application if a gprs/ppp connection is
alive or not?
How can I determine if pppd is currently connecting/disconnecting?

Any other ideas or suggestions?

yours,
Herwig

PlutoPlanet <info@bitart.at> writes:

>Hello World,

>I have written a client-application in C which runs as daemon and
>talks to a server via TCP/IP.

>My client is connected to the internet by a gprs-modem. Right now I
>just start the modem and start pppd (with chat). After that I can
>start the daemon which connects to the server. That is not a very good
>solution, because a gprs and/or ppp connection can break :)

>What is the best way to keep such a connection alive?
>How can I determine from my C-application if a gprs/ppp connection is
>alive or not?
>How can I determine if pppd is currently connecting/disconnecting?

>Any other ideas or suggestions?

The company I'm working for does this (PPP over GPRS, and a TCP/IP
client/server solution) to provide in a production environment a
solution used by public libraries which run a branch of the
library as a so called 'book bus' (a real bus moving around in
town and reader can borrow books in the bus and return them
next week again). The (UNIX-) server runs in the city computer
centre while the client in the bus connected to it runs in XP
having a Linux box for the PPP over GPRS.

The easiest way in the client to detect that all is fine, is that
the used protocol over TCP/IP is working fine.

matthias
--
Matthias Apitz
Manager Technical Support - OCLC PICA GmbH
Gruenwalder Weg 28g - 82041 Oberhaching - Germany
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <m.apitz@oclcpica.org> - w http://www.oclcpica.org/ http://www.UnixArea.de/
b http://gurucubano.blogspot.com/
OCLC PICA GmbH, Geschaeftsfuehrer: Christine Magin-Weeger, Norbert Weinberger
Sitz der Gesellschaft: Oberhaching, HRB Muenchen: 113261

On Sat, 14 Jul 2007 09:48:15 -0700, PlutoPlanet
<info@bitart.at> wrote:
>
>
> Hello World,
>
> I have written a client-application in C which runs as daemon and
> talks to a server via TCP/IP.
>
> My client is connected to the internet by a gprs-modem. Right now I
> just start the modem and start pppd (with chat). After that I can
> start the daemon which connects to the server. That is not a very good
> solution, because a gprs and/or ppp connection can break :)
>
> What is the best way to keep such a connection alive?
> How can I determine from my C-application if a gprs/ppp connection is
> alive or not?
> How can I determine if pppd is currently connecting/disconnecting?
>
Maybe by using lcp-echo-interval and monitoring the log output from
pppd?


--
For every action, there is an equal and opposite criticism.
-- Harrison