Broadening multicasting's reach

SANTA CLARA, California--The growing crush of Internet traffic may get some relief from a technology called IP multicasting, but don't expect it to happen anytime soon.

Multicasting experts from networking, hardware, and software companies met here today at the first IP Multicasting Summit in an effort to spread the gospel. While the technology is starting to make inroads into corporations, consumers won't begin to see the benefits, such as improved video conferencing and audio broadcasts, for some time.

IP (Internet Protocol) multicasting is a method of efficiently distributing information, whether it's a live rock concert or corporate data, over a network to many users at once.

Multicasting contrasts with "unicasting," which transmits separate video, audio, or other data streams to individual users. Instead, multicasting transmits a single stream to multiple users, conserving bandwidth and reducing the stress on network servers.

"From my point of view, IP multicasting is a catalyst that will drive the future of networking," John Hart, senior vice president and chief technical officer for 3Com, said today.

Multicast IP may also play an important role in making "push" technology such as PointCast more widespread. Without multicast IP, data broadcasts from PointCast and other companies could eventually outstrip the capacity of networks, said Judy Estrin, president and CEO of Precept Software.

"Without multicast, the broadcasting people are talking about on the Internet won't happen. Advertisers don't want to reach hundreds of people. They want to reach hundreds of thousands and millions of people, and we don't have the bandwidth without Multicast."

Although the technology is readily available in routers, applications, and other equipment, it is not yet widely used by companies. Nor is it used by consumers, largely because Internet service providers have not begun supporting the protocol, said Precept's Estrin.

According to Estrin, ISPs and users alike will be able to benefit from IP multicasting by relieving networks of traffic snarls and by making new applications possible. But for now, ISPs seem to be dragging their feet on the technology.

"Every ISP is struggling to keep up with capacity requirements. How about using some of those lines more efficiently? Multicast availability can become a competitive advantage, and within a couple of years it will be a necessity," she said.

"ISPs won't do anything unless users push," Estrin said. "The more users ask for access, the quicker the cycle will happen."

Some analysts said IP multicasting is at least two years off from becoming a reality on the Internet, though companies are starting to experiment with it on private enterprise networks.

However, multicasting capabilities are being used a subset of the Internet, known as the Mbone. In use since 1992, the Mbone has been used primarily by researchers and companies to field test Multicast IP.

At least two ISPs, MCI, have begun limited testing of multicasting in their network equipment, though it is used mostly by companies, not consumers.

"ISPs are all in reactive mode," said Don Miller, chief analyst for networking strategies at Dataquest. "Fundamental access is what they haven?t figured out. Eventually, the [ISP] bottom-feeders will start to die out, while the leading carriers will start offering IP multicast."

Many of the companies that are starting to use IP multicasting see it as a better solution than continually installing new network lines because the technology is more scalable.

For example, General Motors is using an application called Starburst Multicast to distribute daily database updates for automobile inventories to 9,000 dealerships over a private network, said Kenneth Miller, chairman of StarBurst Communications, which makes the application. The quantity of data being transmitted prohibited GM from sending it in traditional unicast mode.