Understanding IP Communications: Cisco VoIP Operation November 17
BEFORE you read this posting, please read The fundamentals of VoIP. That post will help you understand what is going on in this one.
This post will explain describe how VoIP works in the Cisco CallManager environment (CCM 4.2). It will explain the communication that happens between the phone and the server, and how the logical structures in the server allow calls to be processed.
As mentioned before there are more granular details in the IP-T world like signaling. In the telecommunications world, signaling is the control of communications between multiple devices. Signaling arbitrates, establishes, and controls a connections allowing communication to exist.
Background
Signaling is basically divided in to two areas; Enterprise and Service Provider.
On the Enterprise side we have several signaling protocols in use. There is SIP, skinny, and H.323.