Round robin outgoing calls

Asterisk Asterisk Support
1

Hi…

We are using Asterisk 11.6 and have 4 sip trunks connected to the Asterisk server…
I’m trying to make the outgoing calls so the first call, calls out over trunk1 and next call over trunk2 and so on. Does someone know how to achieve the configuration in extension.conf so that we can distribute the calls in round-robin fashion?

2

Hi…

I’m been testing different configurations in extensions.conf and this one do the round-robin of outgoing calls:

exten => _X.,1,GotoIf($[${GROUP_COUNT(siptrunk1calls)} >
${GROUP_COUNT(siptrunk2calls)}
]?siptrunk2,${EXTEN},1:siptrunk1,${EXTEN},1)

[siptrunk1]
exten => _X,1,Set(GROUP()=siptrunk1calls)
exten => _X,n,Dial(SIP/${EXTEN}@siptrunk1,60,)

[siptrunk2]
exten => _X,1,Set(GROUP()=siptrunk2calls)
exten => _X,n,Dial(SIP/${EXTEN}@siptrunk2,60,)

It works good with outgoing calls on two sip trunks, but I have 4 siptrunks, and don’t get it to work to distribute the calls with round robin when I try to add 2 more trunks to the dialplan, any hints to succeed with this would be greatly appriciated.

3

You’re on the right way but probably thinking too complicated.
You just need the minimum GROUP_COUNT()-value of Your trunks or in other words: A ranking by GROUP_COUNT(). The trunk with the lowest GROUP_COUNT will be used (except the GROUP_COUNT exceeds the amount of channels available for the trunk, but that’s an addition).

Thus the question is: How to order 4 values ascending? You may do this within any AGI script or You may try to do it in dialplan logic based on any sort algorithm You may find.

Here is an (AEL) example where Test represents Your 4 lines (in the form LineNumber-GROUP_COUNT()&)
After Looping through the sort-algorythm (optimized bubble-sort) the NoOp gives You the mostleft element in the string which will be the Line with the lowest GROUP_COUNT (ascending order)

Set(Test=1-1&2-1&3-0&4-1);
Set(n=4);
while( ${n} > 1 ) {
     Set(newn=1);
     for (i=1; ${i}<${n}-1; i=$[${i}+1]) {
          Set(tmp=${CUT(Test,&,${i})});
          Set(tmp1=${CUT(Test,&,$[${i}+1])});
          if (${CUT(tmp,-,2)} > ${CUT(tmp1,-,2)}) {
               Set(Test1=);
               for (j=1; ${j}<${i}; j=$[${j}+1]) {
                  Set(PUSH(Test1,&)=${CUT(Test,&,${j})});
               }
               Set(PUSH(Test1,&)=${tmp1});
               Set(PUSH(Test1,&)=${tmp});
               for (j=$[${i}+2]; ${j}<=4; j=$[${j}+1]) {
                   Set(PUSH(Test1,&)=${CUT(Test,&,${j})});
               }
               Set(Test=${Test1});
               Set(newn=$[${i}+1]);
          }
      }
      Set(n=${newn});
}
NoOp(${SHIFT(Test,&)});

And - for those who don’t want to implement the sorting itself - Asterisk even has a built-in Sorting function:

Set(Test=1:1,2:1,3:0,4:1);
Set(Test=${SORT(${Test})});
NoOp(${SHIFT(Test)});

The idea is quite the same, the format differs (and needs to be in this way for the SORT-function) and in the example the NoOp just shows the ID of our line which should be used (As after the sort the GROUP_COUNT() is eleminated from the Test-variable in this implementation)

4

Hi…and thank you, got it to work with the built in sorting function in Asterisk…
Now the calls is distributed over the 4 siptrunks…

5

can you please share the full config and script to achieve this