Over the last several years, videoconferencing has emerged as one of the fastest growing segments of the telecommunications industry. But what exactly is videoconferencing? In its simplest form, videoconferencing consists of a camera and display in two rooms, essentially linking the rooms together visually. Through the use of the internet and/or global data networks, the distance between the rooms is essentially infinite.
In order to make this all work, there is a videoconference brain (usually called a codec) that sits at each end and connects to the camera and display. The codec's main function is to encode the camera signal, and decode the camera signal from the other end. Since network bandwidth is costly, the codec compresses the video signals to obtain the best quality based on the available bandwidth.
It is of utmost importance that the audio from the far end arrives matched up to the video. If video fails, the conference can still continue and be mostly effective with audio only. On the other hand, if audio were to fail the conference is essentially over as no meaningful conversation can be had via video alone.
Encryption is also a feature that is added to most enterprise grade videoconferencing products. Each packet is encrypted with a public/private key pair before being sent to the other end. This ensures that nobody can intercept the video or audio content and eavesdrop on the call, gaining access to sensitive information.
The basic videoconference system described above can be expanded to include codecs in many locations. At some point you may wish to have multiple participants in a single video call. This will require either a conference bridge or a codec with multisite capabilities. A bridge or multisite enabled codec simply accepts multiple incoming calls and bridges them together, usually showing all video participants in squares on the screen. This type of call is commonly referred to as continuous presence, meaning that all participants are shown on the screen.
If you need to call through a corporate firewall, there are a number of firewall traversal methods available. This is a complex subject beyond the scope of this article.