How to unload previously loaded destinations in the case of applying multiple ds_select_domain - sr-users

30 Jul 2021


      Hello all,
I have a trouble that is related to the way of usage of dispatcher module.
I am working with Kamailio 5.3.2 and using dispatcher module as load 
balancer to route calls to the media gateways.
My dispatching routes are below as simply,
route[DISPATCH] {
if(ds_select_domain("2", "4")) {
                 route(MYRELAY);
         } else {
                 send_reply("503","Service Unavailable - No MGW");
                 exit;
         }
}
route[MYRELAY] {
         t_on_failure("MYFAILURE");
if(!t_relay()) {
                 sl_reply_error();
         }
         exit;
}
failure_route[MYFAILURE] {
         route(NATMANAGE);
         revert_uri();
if (t_is_canceled()) {
                 exit;
         }
if ($T_reply_code == 408 || $T_reply_code == 503) {
if(ds_next_domain()) {
                         route(MYRELAY);
                 } else {
                         send_reply("503","Service Unavailable");
                         exit;
                 }
         } else {
if(ds_select_domain("6", "4")) {
                         route(MYVMRELAY);
                 } else {
                         send_reply(486,"Busy");
                         exit;
                 }
         }
}
route[MYVMRELAY] {
         t_on_failure("MYVMFAILURE");
if(!t_relay()) {
                 sl_reply_error();
         }
         exit;
}
failure_route[MYVMFAILURE] {
         route(NATMANAGE);
         revert_uri();
if (t_is_canceled()) {
                 exit;
         }
if(ds_next_domain()) {
                 route(MYVMRELAY);
         } else {
                 send_reply("503","Service Unavailable");
                 exit;
         }
}
I have multiple media gateways(setid=2) and voicemail servers(setid=6). 
As can be seen from the configuration,
after first routing, for transaction reply code except 408 or 503, I am 
routing call to the voicemail server using dispatcher.
In that phase, dispatcher module is remembering previously loaded 
destinations that come from first ds_select_domain
and module try to route these destinations in the case that all 
voicemail servers are unavailable.
So basically, I want to unload all destinations comes from previous 
ds_select_domain.
From the documentation, i tried ds_load_update and ds_load_unset 
methods but not worked for me.
Is there any way to overcome that problem or any right usages of these 
methods.
Thank you,
Serdar