Ethernet is proving too slow for the networks of many organisations which want to use multimedia functions and "real time" like video-conferencing. Angus Kidman looks at some of the more recent developments for faster networks.

Published in the Australian Financial Review, September 22 1997

Your network manager has just sent you a terse e-mail. The company's wide-area network, connecting your New York, Melbourne and Sydney branch offices, is overworked and under-performing, she says.

She wants to look into installing a Gigabit Ethernet solution at each, and perhaps examine the feasibility of wide-area ATM links.

And she wants a large chunk of money to do it.

With computer networks now recognised as a vital competitive component of most businesses, you don't want to turn such a request down flat.

But just what are the technology alternatives for speeding up your network?

Most existing corporate networks tend to be based around Ethernet, developed originally by Xerox as a variant of a standard developed by the American Institute of Electrical and Electronic Engineers (IEEE).

Ethernet uses a primitive method of determining when to send across the network -- essentially, check if there's someone on the line, and if there isn't, send out packets of information -- and can send data at up to 10 megabits per second.

It's been widely supported by many leading vendors since 1990, with 24 million new Ethernet network cards sold in 1995, according to International Data Corporation.

Other base-level networking solutions retain some market share, the most notable being IBM's Token Ring standard, which offers a more intelligent method of routing information at up to 16 megabits per second and holds around one-sixth of Ethernet's market share.

Ethernet's dominance has meant that emerging enhanced networking solutions which remain compatible with existing Ethernet-based networks have proved somewhat more popular than entirely new architectures.

While 10 megabits per second seemed very fast back when all that people were exchanging was word processing documents and database files, it quickly became apparent that Ethernet was limited in functionality when using multimedia applications combining large graphics, continuous video and live voice connections, or when the number of users grew rapidly.

As well, solutions for "real-time" applications like video-conferencing need to be able to assign priority for transmitting their data -- something conventional Ethernet can't achieve.

The first two contenders to take networking to the next level, beginning in 1993, were the 100BaseVG standard, whose staunchest support has been Hewlett-Packard; and 100BaseT, an extension of the existing Ethernet standard promoted by Intel and a number of others.

100BaseT has become known as "Fast Ethernet" since it was recognised by the IEEE as the "official" upgrade path from existing Ethernet installations (100BaseVG is compatible with both existing 10 megabit Ethernet and Token Ring networks).

Fast Ethernet has been the more successful of the two solutions in the marketplace (with an estimated 320,000 users hooked up in 1995, according to research firm In-Stat), but the fact that IEEE ratification only occurred last year has meant neither has established a permanent foothold in the market.

If either of the 100 megabits solutions still aren't adequate, ATM (asynchronous transfer mode) technology may get the job done.

ATM comes in a number of flavours, the two most popular transmitting at 25 and 155 megabits per second, and uses "cells" -- packets of a fixed size -- to speed the transmission of data.

Despite a fair degree of hype, though, ATM has yet to really find a footing in the corporate marketplace, due largely to a lack of standardisation and limited ability to be exploited effectively by desktop applications.

A recent networking contender has been Gigabit Ethernet, a standard first proposed by a consortium of vendors.

The main advantage of Gigabit Ethernet is its compatibility with existing Ethernet networks and ability to transmit data at up to 1 gigabit per second.

The main disadvantage is the lack (as yet) of a formalised standard, which means that equipment purchased from one vendor may not inter-operate effectively with other components of the network.

The first wave of commercial Gigabit Ethernet products is expected to hit the market later this year.

Committing to a set of standards in one branch of your network doesn't mean you automatically have to deploy that solution everywhere within your organisations.

For many situations, a mixed bag of networking technologies may be much more effective.

Networks have frequently been designed to conform to the 80:20 rule, which assumes that 80 per cent of network traffic will be local (such as sending e-mail within the same office, or printing out a document) and only 20 per cent will be wide-area (travelling between different servers).

In such a situation, higher-capacity within the local-area network (LAN) is more important than within the wide-area network (WAN).

However, research firm Dataquest predicts that this rule may be inverted in the near future, as companies use intranet technology to link important business processes and information to central servers.

In this situation, with all information revolving around one or more central servers, WAN links become more important than LAN links.