FDDI finally gains backbone network prestige, but new technologies contend

Fiber distributed data interface products have won the confidence of corporate enterprises only to face competition from seemingly more capable network methodologies

Lynn Haber

After more than a decade and with little fanfare, fiber distributed data interface, the 100-megabit-per-second American National Standards Institute network standard, has become the backbone local area network technology of choice in today`s corporate marketplace, with dozens of equipment manufacturers providing products. Whereas vendors of FDDI products expect to see additional growth in this market and continue to roll out new products, competing network technologies cloud FDDI`s future.

For at least the next 12 to 18 months, FDDI is expected to remain the LAN backbone of choice. After that time, industry participants expect FDDI to lose market share to asynchronous transfer mode technology. However, FDDI devices will not disappear. "FDDI will become an interface instead of a network, as will Ethernet and token ring," says Jeffrey Bruckner, managing director at the DMW Group Inc., a computer technology consultancy in Montvale, NJ.

Representing the next generation in network technology, the ATM standard provides bandwidth from 52 Mbits/sec to 622 Mbits/sec and beyond for LAN and wide area network applications. Unlike existing network technologies, ATM is isochronous for the timed delivery of data. It thus accommodates multiple types of data or multimedia, which includes audio and video, unlike existing network architectures. Structured as a data-only network, FDDI can still be tweaked to handle real-time data streams, like voice and video; however, it is not isochronous.

Industry analysts refer to FDDI as the quiet giant because it took a long time for the technology to take hold in the marketplace. Six years ago, 100 Mbits/sec seemed adequate, and at $15,000 to $20,000 per connection, FDDI technology was only sought after by organizations with specialized networked application requirements, such as flight simulation.

But that is no longer the case. Today, FDDI accounts for 57% of the high-speed LAN market, or $251 million in revenues, according to Dataquest Inc., a market-research company based in San Jose, CA. Furthermore, by 1998, Dataquest expects FDDI revenues to more than double to $525 million.

Vendors acclaim FDDI as a stable technology with proven products and point to its attractive characteristics:

Lengthy network diameter distances of 2 and 40 kilometers for multimode and singlemode fiber, respectively.

Dual-homed architecture--a redundant technology--where if one segment goes down, traffic is automatically rerouted onto another segment.

Fault tolerant.

Robust architecture.

Guaranteed access to the media.

Interoperability with existing LAN architectures, such as Ethernet and token ring.

Equipment prices are declining.

Emerging competition

Undoubtedly, the communications industry is excited about emerging network technologies, such as ATM, which is a high-speed local and wide area network technology, but the bottom line is that this standard is still immature. "We expect to enjoy good fourth-quarter growth in our FDDI product line because when it comes to implementing solutions, users don`t want to take risks with immature technology," says Dianna Larrea, high performance networks marketing manager at Digital Equipment Corp. in Littleton, MA.

Digital provides a line of FDDI products for both singlemode and multimode fiber. Larrea notes that the company`s FDDI business has been growing rapidly, with revenues growing at 56% per year, accounting for more than $60 million of its present business.

Needed components

An end-to-end FDDI backbone solution requires four components: network interface cards, routers, switches or hubs, and repeaters. Wade Appelman, manager for product marketing at Cabletron Systems Inc. in Rochester, NH, notes that in the last six months to a year, product prices have dropped as volume shipments have increased and competing technologies have put the squeeze on FDDI equipment manufacturers.

"We can offer customers a bundled FDDI solution today for 50% less than it would have cost a year ago," he says. For example, Appelman cites a 12-port FDDI solution with 12 network interface cards that sold for $40,000 in 1993; today, as a bundled product, it can be purchased for $18,000. On a per-connection basis, FDDI now costs approximately $2000.

As a backbone technology, FDDI allows organizations to interconnect LAN segments across a campus or data center at network speeds many times faster than 4- and 16-Mbit/sec token ring or 10-Mbit/sec Ethernet LANs.

Installation of fiber-optic cable for FDDI in a backbone application is easy, as it commonly includes a run in the elevator shaft or, if necessary, is snaked under the floor or in the ceiling. "The cost of technology keeps dropping, but the labor cost for deploying FDDI keeps increasing," says Jim Metzler, director for data communications research at the Yankee Group Inc. in Boston.

Not only is FDDI capable of transferring large amounts of data quickly and reliably, but it is a robust technology. "FDDI is rich in its manageability, resiliency and redundancy," says Peter Tarrant, vice president for product management at Bay Networks, Santa Clara, CA.

For these reasons, FDDI is also finding applications in other areas of the corporate network infrastructure. In particular, FDDI is being used as a connection between specialized servers, such as for file, database, network and application, where secure transfers of data are critical and bottlenecks are intolerable.

Larrea says that using FDDI between servers is the biggest growth application for FDDI at Digital. Distributed computing, or client/server, requires a high-speed, high-capacity network technology.

Other application areas for FDDI include redundant data centers and metropolitan area networks. Particularly popular in the financial and banking industry, redundant networks provide connections to shadow data centers that are used in emergency situations. With optical fiber as a communications medium, FDDI provides tolerance to interference and security, which make it ideal for these applications.

A clouded future

FDDI is not losing ground to competing technologies. In fact, according to Brad Turner, marketing engineer at 3Com Corp. in Santa Clara, CA, "For any organization looking for an interoperable high-bandwidth standard, FDDI is the only choice," he says.

However, FDDI`s window of opportunity in the marketplace is probably as wide open as it is going to get. "The window will start to shrink unless new market niches are carved out," says Bruckner.

Several high-speed network technologies are encroaching on FDDI turf: copper distributed data interface, switched Ethernet, 100Base-T, 100VG-Anylan and ATM. An established standard, CDDI is a variation of FDDI and uses the same protocol modified to run over copper, or Category 5 unshielded twisted pair. CDDI enables organizations to use existing copper cable rather than have to install optical fiber for FDDI.

Switched 10-Mbit/sec Ethernet provides each client or workgroup with dedicated bandwidth, thereby boosting the performance of an existing network. It also runs over copper cable and, therefore, does not require changing the organization`s cabling infrastructure. Components are also less expensive. An FDDI port, for example, is about $1000 versus $200 to $300 for Ethernet and token ring; network interface controllers cost approximately $1500 for single access and $2500 for dual access for fiber; copper cards generally cost 50% less.

Industry analysts maintain that FDDI has limited potential as a desktop connectivity solution, whereas switched Ethernet has a promising future. Yankee Group`s Metzler says that the market for switched Ethernet is presently $100 million but is expected to reach $1 billion by 1997.

Also known as fast Ethernet, 100Base-T is an evolutionary extension of 10Base-T Ethernet. Like 10-Mbit/sec Ethernet, 100Base-T can be shared or switched implemented.

Switched 10-Mbit/sec Ethernet makes sense as a desktop application, whereas fast Ethernet, or switched fast Ethernet, makes more sense in a server application.

The 100Base-T standard addresses both copper and fiber. The FX fiber version of the standard was, in fact, geared toward equipment manufacturers so they could still sell FDDI products to this emerging market, according to Tarrant. "In a backbone application, 100Base-T FX marries the Ethernet media access control protocol and FDDI technology," he explains. For equipment manufacturers this partnership means continued demand for physical media dependent transceivers.

The 100Base-T FX standard was completed by the IEEE 802.3 committee last October. Product implementation is expected to begin during the next 12 months.

A network technology proposed by the Hewlett-Packard Co., 100VG-Anylan is Ethernet-based and touts easy migration from token ring networks. While 100VG-Anylan is a capable network technology and has its share of supporters, industry watchers are hedging their bets.

A follow-up standard to FDDI, FDDI II was intended to broaden the FDDI design to accommodate isochronous data. However, ATM technology has not only captured the attention of manufacturers, but also it has captured their research and development dollars.

FDDI II products are difficult to find in the marketplace, and it appears that vendors have no intention of pursuing them at this point. "There`s no doubt about it that FDDI II is suffering at the expense of ATM," says 3Com`s Turner. In fact, 3Com, like most other vendors of internetworking products, are directing research resources toward ATM.

Product enhancements to FDDI technology, such as those from Digital, have extended the technology`s viability in the marketplace. u

Lynn Haber is a freelance writer based in Boston.