Internet2: Traffic Moves Into the Very Fast Lane
Wednesday, July 9, 1997
By Richard Poynder
The Financial Times
New high-speed networks being developed by the academic and research community are set to spearhead the transformation of the Internet from today’s unreliable B road into tomorrow’s multimedia superhighway.
Internet2 – the brainchild of a consortium of more than 100 US universities – plans to deliver information at speeds of between 100 and 1,000 times faster than today’s Internet. Designed to provide a range of broadband network applications, including on-line collaborative research, distance teaching and video-conferencing, the new network will connect participating campuses at more than 600 Mbit/s (million bits per second) – fast enough to transmit a 30-volume encyclopedia in less than one second.
To be built over the next two years, Internet2 will eventually operate at speeds as high as 2.4bn bits, or 2.4 gigabits, per second. That compares with just 56,000 bits per second for the fastest modem now available.
Meanwhile in Europe, a new European Union-funded network, TEN-34, was recently launched by a consortium of European national research networks. Initially running at 34 Mbit/s, TEN-34 will later reach 155 Mbit/s.
The primary focus of both projects is to improve Internet access for the academic community. Yet others are expected to benefit. “An explicit goal of Internet2 is to disseminate its developments to the broader networking community, benefiting everyone that uses the Internet,” says Greg Wood, Internet2 communications director.
Although less ambitious than Internet2 in bandwidth terms, TEN-34 will enable the academic community to use real-time multimedia applications – such as video-conferencing and multimedia broadcasting – for the first time on a pan-European basis.
Moreover, as Wood points out, increasing the speed of the network is only part of the task ahead. “Internet2 is not just about faster pipes,” he explains. “It also sets out to implement solutions to other network parameters that are as important as – and in some cases more so – bandwidth.” To understand the issues involved it is helpful to think of the Internet as a national road network. In contrast to the circuit- switched approach of the telephone system – when you pick up the phone, you get a piece of the network entirely dedicated to your call – information sent over the Internet is broken up into small data packets. These packets – like cars on a road – are then mixed with everyone else’s packets, and transmitted across the network as a stream of traffic. The packets then navigate the network by moving from junction to junction.
At each junction a “router” establishes where a packet is going, and passes it on. Like motorway traffic, regardless of the speed with which they travel across the network, packets tend to tail back at the routers.
One of the aims of Internet2, therefore, is to install and test a series of new high-speed “gigapops” (gigabit capacity point of presence) capable of routing packets more quickly through the network. To help achieve this, one of Internet2’s corporate partners, Cisco Systems, plans this autumn to launch a new Gigabit Switch Router designed to support speeds of 2.4 gigabits per second.
Multimedia content poses a more serious challenge. Historically IP – the software protocol responsible for determining how packets are routed across the Internet – has worked on the democratic principle that all packets are equal. While this is adequate for the transmission of files and e-mail messages, it poses problems when attempting real-time applications such as video-conferencing, where voice and vision must be synchronized.
“To avoid undistorted high-quality video on the Internet it is necessary to be able to differentiate between packets,” says John Patrick, vice-president for Internet technology at International Business Machines, an Internet2 corporate partner. “Then you can move packets associated with, say, a video-conference into the passing lane, accelerating them through the network, while putting e-mail packets in the slow lane.” The growing need to distinguish between packets, coupled with increasing calls from corporate users for guaranteed data delivery times, has stimulated the development of a number of new “quality of service” technologies. As well as assessing various methods for packet prioritisation, Internet2 and TEN-34 will be testing the Resource Reservation Protocol (RSVP), designed to allow users to “book” a guaranteed block of Internet bandwidth.
In addition, they will be evaluating IPv6, the next version of the IP protocol.
Among its enhancements is the ability to multicast – instead of swamping the Internet with multiple copies of identical packets, the packets are duplicated only if they arrive at the local network level.
Also being tested is ATM (Asynchronous Transfer Mode) – a very high-speed switching system. Because – unlike IP – it holds a channel open for the duration of a call, ATM is thought to be ideal for the real-time requirements of sound and video. Moreover, its switching approach to data transmission offers benefits over routing methods.
Patrick explains: “Today if you send an e-mail from New York to San Francisco over the Internet, the packets may undergo 15 or more hops from one router to the next before reaching their destination.” Each hop, he adds, slows a packet down and increases the likelihood of packet loss – routers throw packets away when they get overcrowded. Nevertheless, given the pervasiveness of IP, Patrick expects that routing and switching techniques will simply merge.
“In this way your message could be sent to a router directly connected to a switch in New York, which could connect directly to a switch in San Francisco. This in turn could connect to a router in San Francisco, which would pass it to its destination. Instead of 15 router hops there are just two.” With this aim in mind, a number of companies, including Cisco, have developed hybrid techniques combining routing and switching methods. However, upgrading the Internet comes at a price, cautions Dai Davies, general manager of TEN-34: “The Internet has grown up on the myth that it is free,” he says. “But it hasn’t changed network economics. One of the bullets people will have to bite is that if they want quality of service they are going to have to pay for it.”
