Intranets are all about communication. And there is often no better way to communicate than in face-to-face encounters. However, intranets are also about communication outside of physical boundaries like buildings, companies, states, and countries. Often, of course, face-to-face meetings are not practical, due to time limits or budget constraints. In a corporation with branch offices, for example, it can be very expensive and a waste of resources to fly people from all over the country to a single location for a one-hour meeting. With intranet videoconferencing software, however, people can hold face-to-face meetings even though they are located on the other side of the continent from each other. It allows people to see each other and talk to each other while seated at their computers.

Videoconferencing requires a few simple hardware components: a video camera, a microphone, and a sound card for each participating computer. The cost of this hardware has dropped dramatically so that it's quite affordable-and most new computers now come equipped for sound.

There are many different software programs available for videoconferencing on intranets. Microsoft and Netscape, among others, are pushing videoconferencing systems. The longest-standing videoconferencing system on the Internet-CU-See-Me-also has intranet-based videoconferencing. It has been around longer than any other IP-based videoconferencing product, and that's what we'll look at in this chapter.

CU-See-Me videoconferencing works on a client/server model, like many other intranet applications. The CU-See-Me client runs on a local computer, and it can run on many different kinds, including PCs and Macs. When someone wants to join a videoconference, they log onto what's called a reflector-which is really just another name for videoconferencing server software sitting on an intranet server.

Reflectors can handle multiple videoconferences. Videoconferences can be on an ad hoc basis, with people logging in when they want, or they can be scheduled ahead of time. When someone joins a conference, they will see and hear everyone else in the conference-and every person in the conference will be able to see and hear them.

The reflector software is of special benefit to intranet administrators. It allows for security, so that administrators can block unauthorized users from participating in videoconferences. Administrators can restrict access to particular users for specific conferences by using passwords.

The software also allows for load balancing. When intranet use is high overall, for example, it can devote less bandwidth to videoconferencing, to free intranet resources. When use is low, it can devote more bandwidth to videoconferencing.

The videoconferencing software can be used to broadcast information as well. The head of your company, for example, could make announcements live by video to every desktop computer so everyone in the corporation can watch and listen to the announcement simultaneously.

How CU-See-Me Intranet Videoconferencing Works

There are a variety of software programs available that enable people to engage in videoconferences on intranets. One of the earliest and most popular Internet videoconferencing software, CU-See-Me, has also been built to handle intranet videoconferencing. CU-See-Me allows people with desktop computers to have live videoconferences with individuals and groups anywhere across the intranet. Anyone can do videoconferencing with software and hardware that is quite inexpensive.

1. CU-See-Me videoconferencing works on a client/server model. People run the CU-See-Me client on their computer to log into a special server called a reflector. A reflector can host many simultaneous live videoconferences. When you log into a reflector, you can join any conference that exists. When logged into a reflector, a signal goes out regularly from your computer to the reflector, telling others logged in that you are available for a videoconference.
2. The video data is sent using UDP (User Datagram Protocol). Unlike TCP, the UDP does not check for data integrity, nor therefore, does it ask for bad packets to be resent; it just acknowledges the receipt of the data. The result is that UDP provides for a more uninterrupted data transfer and so it provides smoother transfer and is more efficient than TCP when sending video data.
3. You need a video camera, a microphone, and a sound card on your computer. The camera converts your video image into digital data. The CU-See-Me software then compresses and encodes that data, enabling it to be sent across the Internet or intranet. If the data wasn't compressed and encoded, it would be too large to be sent. CU-See-Me also saves bandwidth by sending only the part of the image that has changed. So, for example, if someone's head moves, it will transmit only the moving head, and not the background, which hasn't changed. The person who wants to see your image also has to have the CU-See-Me software. The software decodes the video image, and displays it as video on the person's screen.
4. The reflector software contains many tools that intranet administrators can use to better control videoconferencing. It allows administrators to control the intranet bandwidth devoted to videoconferencing, both to ensure the highest-possible video quality, and also to make sure that the rest of the intranet is given the proper resources. It allows administrators to configure specific conferences at specific times, and also enables security measures such as password-protecting the server, so that only authorized users can log in, or so that only specific intranet users can log into specific conferences. Reflectors can also automatically adjust the rate of video transmission to the amount of traffic on the intranet, sending lower-quality video when traffic is congested, and higher-quality video when traffic is lighter.
5. People on an intranet can participate in videoconferences with people on the Internet (provided the firewall doesn't block the packets). To join an Internet conference, people log into an Internet reflector and participate as they would normally. If they can have a direct connection, they can participate in a videoconference by using the Internet person's IP address.
6. One-on-one conferences do not require going through a reflector. If you know the IP address of someone on the intranet who wants to have a videoconference, you can connect directly to that person's workstation.