SIP
Από AWMN-WiKi
The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences." (cit. RFC 3261).
SIP has the following features:
- Lightweight, in that SIP has only six methods, reducing complexity.
- Transport-independent, because SIP can be used with UDP, TCP, ATM & so on.
- Text-based, allowing for humans to read SIP messages.
Source: www.wikipedia.org

