Multicasting into the Millennium
TR: What technologies do you think will change the way the Internet works?
CERF: One key development is something called multicasting, which vastly improves the ability to send real-time audio and video signals through the Net. The way things work now, a Web server has to send a new copy of the audio or video data to each individual who requests it. With today’s technology, a high-end personal computer “unicasting” on the Internet serves a maximum of several hundred people simultaneously.
TR: What does multicasting do differently?
CERF: Imagine you’d like to share today’s Dilbert strip with some of your colleagues working in a different building. You would not fax 10 separate copies-instead, you might fax one and ask a friend to make copies. Multicasting works along a similar model. A server sends only one copy of information, which can then be reproduced and distributed throughout the network.
TR: How might this be beneficial?
CERF: First, it reduces the unnecessary repetition of traffic on the network for material that needs to get to a large number of recipients at the same time. This applies, for example, to large-scale software distribution, database updates, and securities transactions information.
TR: How close is this notion to a reality?
CERF: Multicasting is already here. A number of Internet service providers, including uunet, are offering multicast services. Last August, MCI and Real Networks announced the establishment of the Real Broadcast Network-an architecture that pushes information content to the periphery of the network and thus multiplies the potential audience dramatically. Before, a live concert that was broadcast on the Internet could reach an audience of only about 10,000 simultaneous users. The Real Broadcast Network makes it possible to fill a much larger “virtual stadium.”
TR: Multicasting seems like a way to turn the Internet from a “many-to-many” network into a broadcast system. Won’t that change the Net’s character?
CERF: Yes and no. While we’ll begin to see many broadcasting applications ported to the Net, we’re not going to lose the many-to-many character that you and so many others appreciate. Also, it’s not as if the Internet has never changed radically before. For many years, the Internet was almost entirely a text-based medium. The Web has certainly altered the character of the Net, but I’m not sure you hear much complaining-although we do need to pay a lot more attention to the presentation of Web content to people with limited sight and hearing.