H.323 protocol in IP based networks

Protocol H.323 introduces call signaling and control, multimedia transmission and management, and bandwidth control for point-to-point and multi-point conferences.

The H.323 protocol is divided into the following three control sections:

• RAS protocol
• Media Control and Transport (H.245) Signaling
• Call Control / Call Setup (H.225)

The RAS protocol is part of the H.323 Recommendation and is a protocol that uses H.323 between endpoints (terminals and gateways) and gatekeepers. The RAS protocol uses port UDP-1719.

The RAS channel is independent of the call and media transmission channel.

Comparison between SIP and H.323 protocols