Difference between H.323 & SIP VoIP Protocols

In the last decade, the Internet has been grown tremendously. The current and hot hot technology is the Voice Over Internet Protocol (VoIP). VoIP is the Internet technology that enables user to use better audio and visual communication from our home computers over Internet. This technology allow you to communicate easily from wherever you are and you have Internet access. Most important factor is, this is cheaper then the regular phone services.

To deliver voice, two types of VOIP protocol used:

H.323

• Well known and commonly used VOIP protocol.
• Created solely for the multimedia communication over IP networks.
• It provides provisions for videoconferencing, data sharing, and audio transmission (VoIP).
• It merges the IETF and ITU-T protocols to form a unified system.
• Though it is still in the early phases, it has been successful to some extent in matching the clarity and speed provided by PSTN networks.
• Ability to recover connection failures and source of connection failure.
• Support Message encoding, Load balancing, Call signaling, Address resolution

SIP

• Designed to setup a “session” between two points.
• No support for multimedia conferencing.
• SIP has large number of problems and has been deployed successfully only in PSTN gateways
• Detection can only be done through timer expiration and re-establishment takes long periods
• Like H.323, SIP also performs the functions of message encoding, load balancing, and address resolution.
• No address-resolution protocol support.
• No ability to detect network failures.
• No backward compatibility which can cause operational failure.