New subject: nanoBTS - First Call Ok, but not others -> I have an ugly hack to fix it

27 Aug 2009

Hi,

I had the exact same problem has described here
http://lists.gnumonks.org/pipermail/openbsc/2009-July/000627.html
That is, the first call worked great but after the first call, no way
to make a second, the BTS would respond with NACK to the CHANnel
ACTIvation requests.

I finally found that the chan_rate field of the channel_mode must be 0
for that request to work. And forcing it to 0 in
rsl_chan_activate_lchan, like this :

--- SNIP ---

        rc = channel_mode_from_lchan(&cm, lchan);
        if (rc < 0)
                return rc;
        cm.chan_rate = 0; // Hack !

-----------

makes the thing work.

But that's obviously not the root cause. I thing the lchan tch_mode
should be GSM48_CMODE_SIGN, so that channel_mode_from_lchan would set
the proper value directly.
But I haven't traced yet why tch_mode is not at the good value for the
second call ...

     Sylvain