Server Operating as a SIP Proxy

In the SIP proxy mode, the entire SIP signaling goes through the SIP proxy. This behavior will help in processes such as billing and it is, by far, the most common choice. The drawback is the overhead caused by the server in the middle of all SIP communications during the session establishment. Remember, RTP packets will always go directly from one endpoint to another, even if the server is working as a SIP proxy.