H.323

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What is H.323?

This is a set of ITU recommendations for methods to provide video conferencing connections using packet networks. First developed for use on Local Area Networks it quickly became relevant for use on IP networks of all types.

H.323 found quick acceptance within the communications industry because its call signaling method was based on established Q.931 developed for ISDN networking. This signal method established a set of standards for call models that were well defined and widely understood. The basic call flow and functional elements of session management established in Q.931 significantly helped quick and widespread adoption of H.323 on packet based networks.

Why is H.323 Important?

Success in communications is being able to reliably initiate a call or session, ensure it is stable while in use, and it must also include the ability to successfully terminate or end the session. While these functions may seem obvious, they are, in fact, quite complex especially on a packet based network.

H.323 quickly enabled successful packet based multimedia communications because it utilized well-established non-packet network standards for call setup, monitoring and take down found in the Q.931 standard (ISDN).

This quick adoption and ease of implementation for H.323 allowed video conferencing manufacturers to quickly introduce packet based communications into their product offerings beginning in the 1990's. Today, nearly every video conferencing product manufactured and all software based video conferencing products use the H.323 protocol in some form for their base level communications.