A SIP server is the main component of our IP 3CX, and mainly deals with the management of all SIP calls in the network. A SIP server is also referred to as a SIP proxy or a registrar. Although the SIP server can be considered the most important part of a SIP-based IP-3CX phone system, it only handles or manages sessions; more specifically, a SIP server can:
The SIP server does not actually transmit or receive any media – this is done by the media server in using the RTP protocol. Within the context of an IP-3CX environment, it is almost always true that the SIP server and its Media server companion reside on the same machine. Do keep in mind, however, that very-high-volume SIP servers (such as a large VoIP provider, for example), may separate their media server to a different machine to better handle the workload, and could also possibly distribute the load to multiple media servers.