I know, but I'm that desperate. On 21 May 2018 at 22:17, Alex Balashov <[email protected]> wrote:
> I think this is the wrong job for Kamailio. > > On Mon, May 21, 2018 at 10:16:20PM +0300, George Diamantopoulos wrote: > > > Hello all, > > > > I've been hitting a wall in getting T.38 fallback to G.711 to work in a > > specific case, and I was wondering if I could use kamailio to the rescue, > > since all my other endeavours have failed miserably. > > > > In short, this is this the scenario where I need to have this > manipulation > > happen: > > - During an established dialog between a SIP endpoint and asterisk (with > > kamailio in the middle acting as proxy), the latter (asterisk) sends a > > re-INVITE with a single offer for m=image with T.38 in the SDP. > > - The other (eccentric) endpoint (yes, it's a Cisco) replies with 200 OK, > > but will reject the T.38 offer in the SDP body instead by including a > port > > number of '0' > > - Instead of falling back to G.711 as configured, asterisk in that case > > will do nothing, and the dialog will eventually end with a BYE (don't > > remember which of the two endpoints will send that, but it doesn't matter > > much) > > > > The thing here is that asterisk *WILL* fallback to G711 with a second > > re-INVITE, if the other endpoint replies to the first T.38 re-INVITE > with a > > negative response (488) instead of a positive one (200) declining the > media > > in the SDP body. I've looked at using freeswitch for a fax gateway > instead, > > but apparently FS doesn't support fallback at all even in the 488 reply > > case, much less in the inactive media stream in 200 OK corner case I'm > > investigating. > > > > So, I thought I'd do that in kamailio and convert those 200 OKs to 488s > > with change_reply_status() from the textopsx module. Of course, the > > universe hates me, and this will fail spectacularly: > > > > > ERROR: textopsx [textopsx.c:301]: ki_change_reply_status(): the class > of > > provisional or positive final replies cannot be changed > > > > So you can't change a reply's "class" with change_reply_status(), only > the > > response code within that class can be manipulated. > > > > I guess my question is now whether there is any way to do this sort of > > transformation with kamailio, perhaps with some other function or method? > > > > If anyone else has had to deal with this problem and come up with a > > different solution I'd be glad to hear it, as neither my head nor the > > surrounding walls can take any more mutual banging at this point. Thanks! > > > > BR, > > George. > > > > P.S. I hate fax > > > _______________________________________________ > > Kamailio (SER) - Users Mailing List > > [email protected] > > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > > > -- > Alex Balashov | Principal | Evariste Systems LLC > > Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) > Web: http://www.evaristesys.com/, http://www.csrpswitch.com/ > > _______________________________________________ > Kamailio (SER) - Users Mailing List > [email protected] > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users >
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