Q: Where is the difference between the H.320 protocol and the H.323 agreement?
A: March 1997 is one of the important moments in the development process of video conference, ITU-T (ITU Telecommunications Commission) released video conferencing standard protocols on local area online, for those The video conferencing system connected to the Internet and intranet provides interoperability, and each manufacturer has launched a video conference product that meets the standard. Prior to this, group video conferencing standard protocols on ISDNs - H.320 have always dominated the technology and product development in the field of video conferencing. The difference between the two is mainly below: 1. Networking structure H.323 bus type network structure does not affect the entire conference and network because there is a temporary failure of a terminal. H.320 The main from the star-string may cause a phenomenon that many network meetings have occurred because there is a single point temporary failure, and there is no fault-tolerance backup mechanism on important nodes. 2. Business Development H.320 is only defined by circuit-exchanged television conference systems, so it is only possible to carry out standard TV conference applications on the transmission network platform, and cannot be extended to a multimedia, multi-application platform. H.323 technology can develop many multimedia applications that are unrelated to the underlying network transmission, such as multimedia video conferencing, multimedia monitoring, multimedia production dispatch command, remote corporate training and education, multimedia call center, online IP phone, online IP fax , Online video on demand and broadcasting, etc., the H.323 technology can be used to add multiple applications and services to the same transport network platform, and the TV conference is only one of its applications. 3. Performance prices than H.320 Due to the restrictions on traditional TV system conference, there is no flexibility and rich features, and whether it is H.320 terminal or H.320 MCU, its user stand-alone cost and user Line usage costs are high. H.323 Advanced TCP / IP technology is highly reduced by providing the same performance and more, which greatly reduces the cost of the user terminal and the user line usage, with high performance price ratio. 4. Data function H.320 system uses T.120 standard to implement data conferencing function (such as electronic whiteboard, file transfer, application sharing), and its data application is included in the H.320 / H.221 multiplexed channel. The T.120 data channel of the H.320 system reaches up to 64kbps. In transmitting large-capacity files, high quality graphics, due to video channels are preempted, image performance quality declines and images are short-lived. H.323 Standards implement data application function (such as electronic whiteboard, file transfer, application sharing) along the T.120 system. But its data application is independent of the H.323 session process, and its data channel does not need to be multiplexed, and separate T.120 data channels directly in TCP or UDP (broadcast), this channel bandwidth can be from several Kbps to several Mbps or 10Mbps adjustable, showing great superiority and flexibility. 5. Multi-Broadcast H.323 is based on the TCP / IP protocol, and the IP protocol has multipoint broadcast function IP MultiCast (RFC1112). Thus easily implement multimedia broadcasting services, such as video broadcasting. The H.320 does not have multipart -p-point broadcast function, and there is no effective under protocol. Therefore, the H.320 system does not have a multipoint broadcast function - that is, the broadcast channel is established. It may use the MCU to use interactive multi-point to implement quasi-broadcast function, not the broadcast channel. Although the H.320 and H.323 systems use the same image and voice codec technology, the quality of the image and sound is the same, but the contrast is the same, but it is not difficult to see from the above advantages. The H.323 protocol standard is the development direction and trend representing the future multimedia video conference and other online multimedia applications. As a traditional technical standard, the H.320 has begun to export the historical stage due to the emergence of new technologies, and inherent limitations and high costs.
