[asterisk-dev] media watchdog for res_fax

Kevin P. Fleming kpfleming at digium.com
Mon Jan 3 08:03:02 CST 2011

On 01/03/2011 07:02 AM, Kristijan Vrban wrote:
> In https://issues.asterisk.org/view.php?id=18557 i noticed that
> app_fax has a watchdog to
> identify a media (T.30) timeout. But res_fax not. The question: Should
> res_fax also have this
> watchdog, would a patch be merged ?
>  From app_fax.c
> /* Watchdog. I have seen situations when remote fax disconnects
> (because of poor line
>     quality) while SpanDSP continues staying in T30_STATE_IV_CTC state forever.
>     To avoid this, we terminate when we see that T30 state does not
> change for 5 minutes.
>     We also terminate application when more than 30 minutes passed regardless of
>     state changes. This is just a precaution measure - no fax should
> take that long */
> #define WATCHDOG_TOTAL_TIMEOUT	30 * 60

I would expect the T.30 stack in the res_fax_* module to handle such 
loss of media... but it doesn't sound like it would be a bad idea for 
res_fax to do this as well.

Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kfleming at digium.com
Check us out at www.digium.com & www.asterisk.org

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