Video over IP categories
Here is a brief description of a few broad categories of video over IP.
Streaming: This is typically used for one-way distribution of video content, such as broadcasts from the CEO to the employees, mandatory safety videos, diversity training, and so on. A popular feature of streaming deployments is the ability to store video near the edges of the network and have users access it "on demand." This is the sort of video that benefits greatly from multicast.
Conferencing: Whether two people or two rooms or six rooms, this is the "talking heads" variety of video over IP. Many older conferencing systems skip the IP part and run the video over ISDN.
Telepresence: This is a relative newcomer. It attempts to offer a more realistic experience with video that is high-definition, images that are life-sized, spatial sound, and other features. In theory, this allows participants to pick up all the body language and much verbal and non-verbal communication that was unavailable with traditional videoconferencing.
Now, for those things to know...
Endpoints: These are the devices on which you watch the video. At a minimum, they'll include a video camera and a TV of some sort. Your options here range from large "room systems" that are dedicated fixtures usually involving a complete remodeling of the conference room in question, laptops or desktops with a video player and webcam, and lots of things in between.
The major decision here is the tradeoff between the convenience and features of "video to the desktop" with the low cost of a shared system in a conference room. If you want to run video to the desktop, make sure that you have your LAN prepared and you're ready to deal with various user issues, such as support when they're trying to run 30 applications at the same time and complaining about poor frame rates, or when they're mobile.
Transport: This is how you're going to get the video from one endpoint to the next. Assuming you want to use IP, your options here are basically to use your organization's data WAN or to build a dedicated video-only network. ISDN is still an option -- and may be a good one depending on what region of the world you're in.
External gateway: This is how you would connect to video systems not on your corporate network. First, you need to determine whether this is a requirement. That is, is there someone you need to do videoconferencing with who isn't in your organization? If so, your options are to set up your own gateway on the Internet or with ISDN circuits, or to purchase a gateway service from your WAN provider or another service provider.
Integration: This is how your video system connects to other IT systems. Popular options include connecting your video system to your email and calendaring application so that users can schedule meetings and conference rooms, or connecting it to instant messaging systems and other data collaboration systems to make it easier to use and to let users share images or work together on a PC application.
More specific things a VoIP manager needs to know deal with video's effect on QoS and potential integration with VoIP. First, QoS Video traffic does need prioritization and protection against data traffic, and when you have both voice and video traffic, it can be challenging to figure out how much bandwidth to size your queues for. You'll want to make sure you have your Call Admission Control worked out before you deploy. Second, if you have both VoIP and videoconferencing, there's a good chance some of your users will want the videophones and the ability to have voice-only participants in your video conferences, where the voice participants are using VoIP in your network.
