[Freeswitch-users] Bug in Q921.c? AVAYA-PBX issue

[Helmut Kuper]

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Hello,

I try to establish a ISDN PRI (euroisdn/Q931) link between FS and an
AVAYA PBX. We use Sangoma A101 and FS revision 10729M on a Ubuntu 8.04
server in a non-root environment.

We experienced a timer problem which led to this FS console error message:

[ERR] Span:0 Q.921() Failed to establish Q.921 link in 3 retries


During anylizing this we found that q921 T203 is never reset when link
is in state "Multiple Frame Mode Established" and SABME frames are
received by FS. So it must timeout regardless if SABME frames are
received or not.
Additionally we found that the default T203 value (10 sec) was too short
for AVAYA (it has to be >=19 sec)

To fix the problem we changed two things in q921.c:

Change T203 default value from 10 sec to 20000 sec
Line 406: trunk->T203Timeout = 20000;

Change Q921T203TimerStart to Q921T203TimerReset to reset T203 on each
received SABME frame
Line 1996: Q921T203TimerReset(trunk, tei);

After recompiling FS the Error disapeared. Next week we will do some
calls over the link to make sure there are no other side effects.

Is it planned to make the q921 timeouts configurable in openzap.conf or
in openzap.conf.xml?

best regards
Helmut


PS: My openzap configs:

openzap.conf

[span wanpipe PRI_1]
trunk_type => E1
b-channel => 1:1-15
d-channel => 1:16
b-channel => 1:17-31




openzap.conf.xml

<configuration name="openzap.conf" description="OpenZAP Configuration">
  <settings>
    <param name="debug" value="7"/>
    <!--<param name="hold-music" value="$${moh_uri}"/>-->
    <!--<param name="enable-analog-option" value="call-swap"/>-->
    <!--<param name="enable-analog-option" value="3-way"/>-->
  </settings>
   <pri_spans>
     <span name="PRI_1">
       <!-- Log Levels: none, alert, crit, err, warning, notice, info,
debug -->
       <param name="q921loglevel" value="debug"/>
       <param name="q931loglevel" value="debug"/>
       <param name="mode" value="user"/>
       <param name="dialect" value="Oh this is not my dialect"/>
       <param name="dialplan" value="XML"/>
       <param name="context" value="default"/>
     </span>
   </pri_spans>
</configuration>

Very interesting here is, that the "dialect" parameter doesn't seem to
have an effect on FS. I use that one above without any errors or warning
and I guess that was not intended.



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