First you got sold on frame relay. Next you lived it. Then you became
comfortable with it.
But now it's time for the really big network - a serious fast-packet network carrying your bedrock applications.
Do you really want dozens, hundreds or even thousands of locations sending frame traffic to an overloaded T-1 frame relay port at a carrier switch near your data center? If not, that scary alternative you've been avoiding for years now will be staring you in the face: ATM.
The explosion of T-3 and fractional T-3 traffic demands by corporations over the past 18 months is resurrecting wide-area ATM, once given up for dead except for the carriers' own backbones. Big companies and government agencies are finding that no amount of parallel frame relay permanent virtual circuits or oversubscription of frame relay ports can handle the mass of payroll, inventory, transaction and imaging data that must find its way to hosts and servers.
Except for MCI Communications Corp., the major carriers do not offer frame relay above T-1 speeds. Full and fractional T-3 private lines still are an option, of course. But they're zooming in price as Internet service providers compete with enterprises to obtain carrier bandwidth. What's left? ATM, which is beginning to gain a place in corporate America as the high-speed alternative into data centers and major enterprise WAN hubs.
Ask Ernst & Young LLP, a large accounting and consulting firm. As its Sprint Corp. frame relay network grew in the early 1990s, it carved out a core backbone of eight regional sites, all linked in a meshed configuration with dual T-1 frame relay circuits. Some 160 other sites connected with the network, typically with a 56K bit/sec frame relay link to one of the backbone sites, says Russ Davis, assistant director of network services.
But problems cropped up in 1995 and 1996 as Ernst & Young boosted its number of Lotus Development Corp.'s Lotus Notes servers to 400 and started testing delay-sensitive workflow applications from SAP AG and PeopleSoft, Inc. Latency just across the WAN rose as high as 180 milliseconds due to increased congestion.
So Ernst & Young moved to T-3 ATM in the core, with Cisco Systems, Inc. Model 7513 routers supporting ATM to the other backbone sites and frame relay to the branches. Now data travels across the country in 62 milliseconds. "The latency is extremely low," Davis says. "The stuff is definitely screaming."
Neither Ernst & Young nor any other com-pany is junking its frame relay network, you'll note. Instead, frame relay-to-ATM interworking - either in the router or, as AT&T now is pushing, within the carrier switch - is the order of the day. That's quite a change from two years ago, when carriers raced to introduce T-1 ATM in a quest for all-ATM user WANs. But just as local-area ATM hasn't reached the desktop, T-1 ATM wasn't low speed enough to reach the branch nodes in most companies' WANs.
Even the world's largest companies have small offices, after all. And what they don't have is unlimited budgets, just like their smaller brethren. Show us an ordinary branch office of a Fortune 1000 company and what they're likely to have, in 1998 and beyond, is a frame relay connection to the world.
