Hello,

On 29/09/14 22:47, João Vitor Arruda wrote:

Hi folks,

I have a question related with the limited number of branches being 12 in config.h

#define MAX_BRANCHES            12      /*!< maximum number of branches per transaction */

I am trying to implement a Call Group that consists in trying each member of the group (that can result in a parallel forking when lookup() is used) in sequence (similar to serial forking).

Currently I have written code that is similar to the one described here:

                http://www.kamailio.org/dokuwiki/dokuphp/tutorials:avpops#serial_forking

The only difference is that for each member I call lookup() and then in the failure_route(), I pull the next member from the stack and call lookup() again.  The code works fine when used for groups with less than 12 members.  However, call groups with 12 or more members fails as I can never reach remaining extensions once MAX_BRANCHES limit is reached.

I've tried another approach using the functions described here:

                http://kamailio.org/docs/modules/4.1.x/modules/tm.html#tm.serial_forking

but it too uses a new branch for every group member until the 12 limit is reached out.

I also tried to use the functions "remove_branch(index)" and "clear_branches()" (both of which are poorly documented.  In fact the only reference I ever found for these functions was here: http://www.kamailio.org/wiki/features/new-in-3.2.x#functions).  Unfortunately, I wasn't able to prevent the MAX_BRANCHES limit from being reached.

Ultimately, my goal is to have a limitless Call Group.  Do you have any suggestions? (other than increasing the hard coded MAX_BRANCHES limit)

the easiest is probably recompiling with more branches. There was someone saying that he is going to submit a patch on making the number of branches more dynamic, but I haven't seen it back.

From routing point of view, you can try a workaround with:
- append 11 branches to the same sip address (see append_branch() function) and relay
- be sure you allow traffic from server itself
- now you get 12 INVITE coming back to kamailio, so you get 12 INVITE requests and you can set 12 different destinations for each, ending up with 144 over-all branches in the group call
- if you need more, you can loop back again one or more of those INVITE requests with branches pointing to same SIP address

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda

_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users@lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users