SIP and H.323 ComparisonBoth SIP and H.323 are quite dated, though. SIP and H.323 were both initiated in 1996. Last RFC 3261 for SIP approved in 2002, H.323v6 approved in 2006. Although, SIP still gets new RFCs that expand its functionality. For example, SIMPLE and DualVideo. H.323 works at bitfields that in ideal conditions of implementation (not online) saves network traffic as compared to SIP. However, in modern conditions of the rapid spread of broadband Internet, this advantage does not look so important. SIP is an application layer protocol for the OSI model. Principles underlying SIP protocol:
- Simplicity: includes only six methods.
- The independence of the transport layer. It may use UDP, TCP, ATM, etc.
- Personal mobility of users. Users can move within a network without any restrictions due to the assignment of a unique identifier for each user.
- Network scalability. Network structure based on the SIP protocol makes it easy to expand and increase its number of components.
- Extensibility. The protocol is characterized by the possibility to supplement it with new features when new services appear.
- Integration into the existing Internet protocol stack. SIP is part of a global multimedia architecture developed by the IETF. The architecture also includes RSVP, RTP, RTSP, SDP protocols.
- Interaction with other signaling protocols. SIP protocol can be used in conjunction with other IP telephony protocols, PSTN protocols, and to communicate with the smart grid.