SIP protocol - Standing TCP connection
The Session Initiation Protocol ( SIP ) is a signalling protocol used for establishing and closing multimedia sessions such us voice and video call over the internet. Using SIP is also possible to create video conferencing , streaming multimedia distribution (for online gaming for instance), send instant messages , handle presence information (online/offlie with rich status information). The protocol can be used for creating, modifying and terminating two-party ( unicast ) or multiparty ( multicast ) sessions consisting of one or several media streams. SIP clients typically use TCP or UDP to connect to SIP servers and other SIP endpoints. SIP is primarily used in setting up and tearing down voice or video calls. However, it can be used in any application where session initiation is a requirement. These include Event Subscription and Notification, Terminal mobility and so on. There are a large number of SIP-related RFCs that define behavior for such applications. All voice/video c...