When I try to call someone I want to hear musiconhold with ringing sound. My dial plan on below This dial plan is working but I can’t hear ringing sound. Do you have any idea about it?
The problem is that, sometimes, it is not an easy task for a UAC to
know whether it will be receiving early media or it should generate
local ringing. A UAS can send early media without using reliable
provisional responses (very simple UASs do that) or it can send an
answer in a reliable provisional response without any intention of
sending early media (this is the case when preconditions are used).
Therefore, by only looking at the SIP signalling, a UAC cannot be
sure whether or not there will be early media for a particular
session. The UAC needs to check if media packets are arriving at a
given moment.