I am very interested to learn the technology that works to transfer user call from IVR server to agent PC's.
From my understanding, a client is needed to be installed in agents' PCs. A ringing popup should appear in agents PC to answer.
Please help explaining how calls from IVR server distributed to agents PCs.
thanks.
Restcomm uses Session Initiation Protocol (SIP) - (RFC 3261) which is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants.
That means, if a Client dials to Restcomm, and Restcomm needs to redirect this call to another Client, it will make it using the SIP since the first call until reach the agent PC's. The Client must have a SIP Client software installed in his PC (as you mentioned) or mobile, and should already make the first contact with the server to inform that he is online. This first contact happens over the SIP message "REGISTER", after that, the calls are started by the SIP message "INVITE".
So, learn about SIP is a good start to understand the technologies involved in call flows executed by Restcomm. Here follows some good links about SIP that will probably guide you to a more clear perspective:
1 - http://arstechnica.com/business/2009/12/wired-for-sound-how-sip-won-the-voip-protocol-wars/
2 - http://arstechnica.com/business/2010/01/voip-in-depth-an-introduction-to-the-sip-protocol-part-1/
3 - http://arstechnica.com/tech-policy/2010/03/voip-in-depth-an-introduction-to-the-sip-protocol-part-2/
I hope it helps :)