The shrinking world of ATM

San Jose, Calif.

ATM, once considered the ultimate end-to-end enterprise network technology, is getting pushed out of the campus network picture.

ATM's world is shrinking because of the emergence of Gigabit Ethernet, frame-based quality-of-service (QoS) features and IP switching, according to a sampling of the 4,000 attendees at this week's ATM Year '97 show here.

At last year's show, attendees basically conceded the desktop LAN market to technologies other than ATM.

"Now that the end-to-end utopian idea of ATM is gone, why bother with cells anywhere in the LAN?" asked Steve Bell, president of Bell Consulting, Inc. in Cupertino, Calif. "We've known for a while that it doesn't make sense at the desktop. Now we're starting to realize that the merits of ATM in the enterprise are also dubious."

Customers such as Joseph Giroux are leaning away from ATM and toward Gigabit Ethernet for the backbone.

"We're already using 100M bit/sec Ethernet, so I'm thinking that it might just be easier to stick with a technology that we already know," said Giroux, director of information systems at West Valley/Mission College in Saratoga, Calif.

ATM gurus like John McQuillan, president of McQuillan Consulting, Inc. of Concord, Mass., and chairman of the ATM Year '97 show, did not go quite so far as to concede the campus to technologies other than ATM. But he did make it clear that ATM's chief role will be in WANs.

What's spooking ATM?

Among the biggest issues for ATM is Gigabit Ethernet. This technology, which is expected to be standardized in early 1998, carries data at 1G bit/sec while retaining the Ethernet frame format. Many analysts think customers will prefer to use a familiar, frame-based technology for simplicity and easy integration with existing networks.

"Customers like to upgrade their networks because it reinforces a correct earlier decision, and they hate to have to replace anything because it is an admission of error and can be expensive and complex to start over," McQuillan said. And that does not bode well for ATM.

Before Gigabit Ethernet's emergence, ATM was the only speedy backbone game in town. So customers could justify the leap to ATM - and all the new equipment and training that went with it. ATM hardliners such as FORE Systems, Inc. are still very much focused on ATM in the backbone, but others such as 3Com Corp. and Cisco Systems, Inc. are hedging their bets.

ATM cannot even boast having superior multimedia capabilities anymore, observers said.

Although once thought limited to the ATM world, QoS capabilities soon will be available in Gigabit Ethernet switches using IP protocols like Resource Reservation Protocol. Customers will no longer have to make the leap to ATM to gain the benefits of bandwidth reservation and other key QoS parameters necessary for handling multimedia traffic.

Ironically, IP Switching also has stolen much of ATM's thunder. IP Switching was originally proposed by Ipsilon Networks, Inc. as an ATM-centric method of zipping IP traffic across a network. But the industry is now embracing the idea that IP can be switched using a frame switch or gigabit router, eliminating the need for ATM switches.

And so it seems difficult to discern any significant ATM advantage over frame technologies like Gigabit Ethernet, Bell said.

"ATM's advantage over frames isn't bandwidth, it isn't QoS and it isn't price, Bell said. "So the ATM community has left the door wide-open for the Ethernet people to come in with a good alternative."

The only advantage ATM may still hold over Gigabit Ethernet is timing. ATM is the sole choice for customers who need a high-speed, multimedia LAN backbone today.

But it will only be about 18 months before Gigabit Ethernet gear with all of the ATM-like features is widely available, industry observers said.

"Just like some strong trees won't survive in a forest because they are shaded out by bigger trees, a lot of excellent technologies just don't make it and never take root," McQuillan said.