VNS Video-Over-IP Guidelines

Overview The North Carolina Information Highway (NCIH) Video Conferencing Network has been used for years to provide videoconferencing across the State network of universities, community colleges, high schools and state agencies.  Connections are established between sites using a circuit switching technology that physically connects each site together at a specified time for a specified period using a scheduler.  The protocol or standard that is used for this network is known as the H.320 protocol. IP videoconferencing (H.323) was engineered for videoconferencing that takes place on a data network without any quality-of-service, such as the Internet. Such networks are not intended for delivery of sensitive near real-time applications. The data network is used for multiple purposes: e-mail, web browsing, and other activities are inter-mixed with IP videoconferencing. IP videoconferencing systems are typically less expensive than older H.320 systems. IP Videoconferencing provides the ability to connect to a larger global network of users that are not dependent on a dedicated circuit switched network.  Dialing the IP address of the distant end’s system will connect IP video systems together.  The routers of the IP world are used to route video packets to their intended destination. The dedicated H.320 circuit networks provided predictable quality over dedicated paths.  However, on IP networks, since video packets are routed through a combination of dedicated circuits, non-switched connections, and large metropolitan networks, it is important to maintain data packet integrity of real-time video data through every connection, all the way to the other video endpoint.  Real-time video must arrive fast and error free at its destination. The audio/video information within a videoconference is segmented into chunks by the application, encoded and compressed, put into a series of data packets and sent over the network to the remote end at basically constant intervals. The data packets arrive at their destination at varying times, and often out of order. To keep the "real time" impression of an interactive videoconference, the packets must arrive, on time and in time to be re-ordered for delivery through the videoconferencing terminal. If your site is using the NCIH network it is connected to the network using some type of transmission circuit or what is commonly referred to as connectivity.  Your site may have a dedicated circuit provided by the State of NC.  This dedicated circuit provides connectivity from your site to the larger State owned data, video, and voice network.  Internet connectivity may also be provided to your site using the same dedicated circuit.  Currently ITS Video Network Services operates the legacy H.320 video network and the new H.323 IP video network.  There are hourly and monthly subscription rates for video services.  ITS Video Network Services is migrating sites from the legacy H.320 network to the H.323 network.  Cost savings from the migration will prove to be substantial over the next decade, and will provide greater worldwide connectivity for all subscribers. ITS Video Network Services has developed these guidelines to ensure the highest possible degree of quality for video over IP.  These guidelines cover the basic configuration of hardware and network architecture and components that are critical to reliable video communications.