THE ultra-high speed, turbo-charged Internet of the next millennium moved a step closer to reality last week as MCI-WorldCom completed a blisteringly fast leg of the US government-sponsored Next Generation Internet project.
The fibreoptic segment, which links San Francisco and Los Angeles, is part of MCI WorldCom's Very High Performance Backbone Network Service (vBNS), a high-speed, research-only private Internet connecting supercomputing centres and university computer research departments. The upgraded link now operates at quadruple its former speed.
In tandem with the similar, university-led Internet 2 project (I2), NGI is not an actual, physical Internet, but a research-only programme intended to create the infrastructure and applications for the Internet of the future. The vBNS, built by MCI WorldCom in a five-year, co-operative agreement with the US National Science Foundation, forms the network backbone for the NGI project. Most major US cities are now networked into the vBNS.
The San Francisco-to-Los Angeles leg of vBNS strings together California's leading universities and five supercomputing centres and is now the fastest Internet link in the world, capable of moving data at 2.5 gigabits per second, up from its previous 622 megabits per second (a gigabit is 1,000 megabits). In comparison, most corporate networks transfer data at 10-100 megabits per second. A standard home computer modem crawls along at 56 kilobits per second - 1/20th of a megabit.
Such speeds bring the real possibility of Internet-based "distributed virtual environments" - computer-generated visual worlds where people can gather to interact in real time. Until now, such environments have seemed more the realm of science fiction than fact, but MCI's researchers insist their moment has arrived.
"In essence, this is a distributed Holodeck," said MCI's lead engineer for vBNS Mr Rick Wilder, referring to the holographic environment used for entertainment by crew members in the show Star Trek: the Next Generation.
According to Dr Vinton Cerf, one of the Net's pioneers who is now MCI WorldCom's senior vice-president of Internet architecture and technology, and also was part of the Irish Government's Advisory Committee on Telecommunications: "The vBNS is really a testbed for extremely high bandwidth facilities." What makes the new service unique, he says, is that it can offer "sustained bandwidth" of 622 megabits per second for a specific application due to advances in routing traffic over the network.
This is important for ultra-high bandwidth applications that require the creation of 3D worlds and is a limitation on such applications on the existing Internet because of the way in which data is sent over the network.
Data sent from one site is broken down into much smaller chunks of information called "packets". The packets take numerous routes over the Internet - directed by routers and switches, they each try to find the most direct pathway available - and eventually arrive at their destination, where they reassemble themselves.
Sometimes packets get lost or delayed, an occurrence which passes unnoticed most of the time because each packet is so small and inconsequential. But with 3D applications, any fluctuation in the speed at which data is sent and the reliability with which it arrives will disrupt the real time continuity of the environment. With the kinds of applications being considered by the NGI project, delays could have potentially disastrous consequences. For example, researchers believe that virtual environments of the future could enable a surgeon in California to perform an operation in Thailand. Even the slightest lag in the arrival of data across the Internet could threaten the patient's life.
However, such uses of the Net are still some way in the future, acknowledged Dr Cerf. "We've got plenty more mountains to climb." The upgrade to the Californian segment of the vBNS was achieved using techniques which themselves stretch the imagination - using multicoloured light rather than installing more fibreoptic cable. Engineers increased the capacity of a fibre by sending different colours of light through it. Each colour handles different types of data, allowing a single fibre to carry data more efficiently.
"We didn't have to lay down additional fibre, but light it up like a Christmas tree in order to create additional capacity," said Dr Cerf . "As a matter of fact, we've only just begun to mine the many colours of light that enable us to acquire additional capacity."
Asked why the network was installed first in California, Dr Cerf replied, "Doesn't all weird new stuff come out of California?" Although an MCI spokeswoman was quick to note that Dr Cerf himself came from California, he added that the state was chosen because of the concentration of top-level research facilities on this particular segment of the vBNS. The sites include Stanford University, the University of Southern California, the University of California campuses at Berkeley, Los Angeles and other locations, and the California Institute of Technology. Eventually, Dr Cerf said, the high bandwidth applications and the infrastructure developments pioneered on the NGI will become part of the public Internet of the future.
