Ozeki VoIP SDK - Product Guide
Protocols for VoIP connection
To be able to provide VoIP services several protocols need to be employed. On
this page we focus on the four most common ones used to describe VoIP connections.
Protocol is a generic term, a standard that describes how the respective participants communicate with each other. For transmitting audio and video packets between communicating computers Real-Time Protocol (RTP) is used worldwide. But before audio or video media are transmitted between computers other protocols need to be used to find the remote device and to define the means by which media will be transmitted between the two devices. These are call-signaling protocols, such as Session Initiation Protocol (SIP).
VoIP connections are basically described with the following protocols:
- SIP: Session Initialization Protocol
This protocol creates, modifies, and terminates calls
- RFC: Request for Comments
RFC documents concerning SIP
- UDP: User Datagram Protocol
- SDP: Session Description Protocol
It describes media components and conciliates between participants (codecs and transfer protocols)
- RTP: Real-time Transport Protocol
It transmits audio and video packets between communicating computers over the network. To identify packages it uses time stamps and ordinal numbers.
- RTCP: Real-Time Transport Protocol
- H323 Protocol