How does CM choose which SIP trunk member get used?

[scottrutledge]

Customer is using a SIP dialer, and has a single SIG group and two trunk groups. How does CM decide which trunk group routes the call?

Trunks groups don't match the SIP domain, the SIG group does.

I guess I would think that one group would fill up before the other takes the call, but it doesn't, nor it it random. Member 5 and 6 on the second TG always takes the first two calls and the 3rd call will be on the other TG.

[bagarcia]

Customer is using a SIP dialer, and has a single SIG group and two trunk groups. How does CM decide which trunk group routes the call?

Trunks groups don't match the SIP domain, the SIG group does.

I guess I would think that one group would fill up before the other takes the call, but it doesn't, nor it it random. Member 5 and 6 on the second TG always takes the first two calls and the 3rd call will be on the other TG.

CM routes outbound calls based on preferences in the route pattern. On inbound calls, if two groups are being served by one signaling group, then the calls will load balance between the two trunk groups. In my testing, I saw two calls come into the first trunk group, then one call into 2nd trunk group, then next call to first trunk group and so on. Having tested this, I now want to ask why would you have two trunk groups for one SIP signaling group? What is it buying you?