PPP Stack

PPP Stack

[John Paul King]

(BTW, sorry if I've sent this repeatedly--having problems w/ Ximian
Evolution)

I'm not sure if anyone else had this problem, but I thought that I would
pass along the information.  I was using the eCos PPP stack in conjunction
with an EB40A, and I was able to establish a link w/ a Linux peer flawlessly
(btw, thanks for the cool stack--I was able to create a program in Linux and
have it immediately work in eCos!); however, when trying to connect to
another device (in particular, a Kyocera 1xRTT module), a link never
occurred (i.e., the Kyocera module never even tried to respond to PPP
packets sent).  Further inspection showed that the eCos stack did not send
out an initial "flag sequence", and I assume the module timed out before the
next frame was sent (i.e., wasn't able the use the previous ending "flag
sequence" as the beginning "flag sequence" of the new frame).  I modified
the code in "pppasyncstart" such that the "flag sequence (0x7e)" is sent
before every frame, and this seemed to worked great for my application;
however, I'm not sure this would be best for all users since a "NULL frame"
would possibly have to be digested by all possible peers.  Anyhow, let me
know if this is the right way to go.  Thanks for the great operating system.

John Paul King

Re: PPP Stack

[Jonathan Larmour]

John Paul King wrote:
> (BTW, sorry if I've sent this repeatedly--having problems w/ Ximian
> Evolution)
> 
> I'm not sure if anyone else had this problem, but I thought that I would
> pass along the information.  I was using the eCos PPP stack in conjunction
> with an EB40A, and I was able to establish a link w/ a Linux peer flawlessly
> (btw, thanks for the cool stack--I was able to create a program in Linux and
> have it immediately work in eCos!); however, when trying to connect to
> another device (in particular, a Kyocera 1xRTT module), a link never
> occurred (i.e., the Kyocera module never even tried to respond to PPP
> packets sent).  Further inspection showed that the eCos stack did not send
> out an initial "flag sequence", and I assume the module timed out before the
> next frame was sent (i.e., wasn't able the use the previous ending "flag
> sequence" as the beginning "flag sequence" of the new frame).  I modified
> the code in "pppasyncstart" such that the "flag sequence (0x7e)" is sent
> before every frame, and this seemed to worked great for my application;
> however, I'm not sure this would be best for all users since a "NULL frame"
> would possibly have to be digested by all possible peers.  Anyhow, let me
> know if this is the right way to go.  Thanks for the great operating system.

I don't know PPP/LCP off the top of my head, but I suggest you have a look 
at the relevant RFCs as that's the only way to know what's correct and 
allowed. If you find something relevant in there, feel free to post 
something in our bugzilla database (see the website).

Jifl
-- 
eCosCentric    http://www.eCosCentric.com/    The eCos and RedBoot experts
--["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine