The networking industry is under-going a sweeping change that canbe summed up in one word: con-vergence. Convergence repre-sents the merger of voice and

data onto a unified network. Tradition-ally, companies have run voice over a cir-cuit-switched telephone network and dataover a packet-based network.

“What we see happening is a businessneed and a technology push toward net-work convergence,” said Rich Klapman,product director for AT&T’s integratednetworks business. “The need for con-vergence is arising at the same time thattechnology is making it possible.”

Reflecting the rising popularity of theInternet and IP technology, the con-verged networks are or eventually will beprimarily packet- and IP-based, for bothvoice and data services. Some carrierscurrently are offering converged servicesover a combination of packet- and cir-cuit-based networks.

However, it is easier to converge voiceand data services over single packet-based networks. In addition, becausepacket-switched networks send packetsalong any available channel on a trans-mission route, they are more efficient torun than the traditional circuit-switched

telephone networks, which use an entirechannel for a single transmission.

Also, converged networks would helpadministrators by giving them only oneplatform to worry about.

For these reasons, said David Yedwab,vice president of Eastern ManagementGroup, a research and consulting firm,“Converged networks will lead to lowercosts for building and managing networksand, ultimately, to lower prices for users.”

Such technologies as Ethernet, ATM,and frame relay give users an array oftransmission environments and let anycompany transmit voice and video asdata packets at speeds as high as Sonet’s(synchronous optical network’s) top9.953-Gbps rate.

Despite the advantages, early adoptersof converged networks can also expectlimited service availability and some lin-gering technical problems.

Nonetheless, converged networks aregrabbing the attention of new and oldtelecommunications service providers,equipment vendors, and potential users.

Users can either build their own con-verged networks or buy services from aconverged network, such as MCIWorldCom’s On-Net, Sprint Communi-cations’ Integrated On Demand (ION),or Qwest Communications’ Macro Ca-pacity Fiber Network.

The figure on the next page shows howcompanies and consumers might use thevarious types of converged networks.

The Gartner Group, a technologyresearch company, predicts that withinthe next five years, approximately three-quarters of Fortune 1000 companies willuse some type of converged network.

One of the first organizations to imple-ment a converged network was St. Luke’sShawnee Mission Health System inKansas City, Missouri. The health careprovider uses the network to transmitvoice, data, and radiological imagesamong eight scattered facilities.

John Wade, St. Luke’s vice presidentand chief information officer, said thenetwork has proven very functional andefficient. Wade estimates that theapproach has slashed network operatingcosts by about 12 percent and that sav-ings could climb to as high as 30 percentas more users link to the network.

Based on this potential, some telecom-munications executives have started newcompanies, such as Level 3 Communi-cations, dedicated to start-from-scratchconverged networks.

In addition, there has been a furiousround of mergers, acquisitions, and part-nerships, as carriers and equipment ven-dors try to build the technical andmanagement skills needed to cope withcutting-edge networking technologies.

For example, AT&T merged withcable TV giant Tele-CommunicationsInc. to gain access to TCI’s broadbandnetwork. Also, voice-technology pioneerLucent Technologies acquired data-net-working equipment vendor AscendCommunications. In addition, NorthernTelecom, a leading telephone company,purchased Bay Networks, a major data-

ConvergenceReshapes the

NetworkingIndustry

John Edwards

14 Computer

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Editor: Lee Garber, Computer, 10662 LosVaqueros Circle, PO Box 3014, Los Alamitos,CA 90720-1314; l.garber@computer.org

networking equipment vendor, to formNortel Networks.

CONVERGED-NETWORK TECHNOLOGYRapid advances in networking equip-

ment are encouraging convergence.

Networking equipmentOver the past several months, vendors

such as Cisco Systems, Lucent, NortelNetworks, and 3Com have either signif-icantly upgraded or completely replacedtheir router and switch product lines tohandle converged traffic.

For example, Lucent upgraded its5ESS switch from circuit to packet tech-nology last year.

The switch now supports data ser-vices—including Internet access, DSL(digital subscriber line), or private lines—bundled with voice services, said MichaelMeyers, Lucent’s North American mar-keting director for switching and accesssolutions.

Meanwhile, other companies are usingsoftware upgrades to voice-enable theirformerly data-only routers.

In addition, Cisco’s new Catalyst 600

multigigabit switches now include qual-ity-of-service (QoS) features, which arecritical for converged networks becausethey permit transmission of voice, real-time video, and other high-priority traf-fic before less important data traffic.

Transmission technologiesVendors are already using such tech-

nologies as frame relay, Ethernet, ATM,and DSL with converged networks.

Frame relay is sometimes used on con-verged networks because of its wide-spread availability and relatively highbandwidth. However, many industryobservers expect it to be supplanted bytechnologies that are easier to install andmanage, such as Ethernet and ATM.

Ethernet is already being used onmany converged networks, and GigabitEthernet is poised to play a major role onthe high-speed corporate backbone.Although Ethernet does not offer QoS, itcan be used with RSVP (the resourcereservation protocol) to improve the ser-vice it provides for high-priority trans-missions.

Many converged-network service

providers rely on ATM because all com-monly used protocols, including IP, canride over it and maintain QoS. This isimportant for voice and other traffic thatdemand uninterrupted transmission.

Many smaller businesses that can’tafford their own high-speed networks orhigh-speed access lines are turning to cablemodems or to DSL technology, whichoffer transmission rates of 128 Kbps to 7Mbps at relatively low cost over standardcopper wiring. These technologies providecompanies with an inexpensive way to getenough bandwidth to access a serviceprovider’s converged services.

CONCERNS AND CHALLENGESSeveral problems could pose at least

temporary roadblocks to widespreadadoption of converged networks.

For example, the networks aren’twidely available and probably won’t befor at least a few more years.

Also, full-motion, real-time video con-sumes a tremendous amount of band-width, which could pose problems forusers with slower access technologies.

However, bandwidth is currently

May 1999 15

Corporations could access converged voice and data network services from a network service provider (telephone or cable TV company) or Internetservice provider, via a high-bandwidth modem. Corporations could also access converged services by running their transmissions through a voice,data, and video switch in their own networks and then to a network service provider or an ISP. Corporations could also directly access services fromone of the new carriers that are building their own all-IP converged networks.

Phone

Business

PC

Video-conferencing

Fax

DSL

Cable

Carrierwith all-IPconvergednetwork

Voice/data/videoswitch

Localphone

company

Long-distancephone

company

Call or faxrecipient

ISP

Internet

Call or faxrecipient

High-speed modem

Cable TVprovider

Central switchingoffice

16 Computer

expense is usually far less than startingfrom scratch with separate networks forvoice and data, said Dan Moore, directorof business development for NortelNetworks’ Carrier Solutions Unit.

I t’s difficult to predict how fast compa-nies will adopt converged-networktechnology, said Eastern Management’s

Yedwab. However, he said, “It’s going tohappen faster than the 10-year timeperiod it took to transition from analogto digital [networks].”

He said, “I would say sometime late in2001 or early 2002, we’ll start really see-ing what I call broad deployment.”

As the converged network heads intothe 21st century, Speyer sees networkinstallation and management costs head-ing down. He said this will occur largelybecause of the mass production and eas-

widely available to many network users,said Marty Kaplan, Sprint’s chief tech-nology officer.

Also, within a few years, emergingcommunications technologies, includingthose based on fiber optics, will increasetransmission speeds and reduce band-width prices, said Jack Danahy, directorof planning for GTE Internetworking, amajor network backbone provider.

Nonetheless, service providers andequipment vendors still haven’t ad-dressed some important QoS issues,according to Michael Speyer, associatedirector of the Yankee Group, a technol-ogy research firm. For example, vendorsare still working with a number of com-peting and conflicting QoS schemes.

Finally, converged networks entailinstallation costs. However, for organi-zations starting from scratch or replac-ing their existing network systems, the

ier design of equipment that will be per-mitted when the industry works througha tangle of proposed network-servicesstandards in such areas as streamingaudio and video, IP telephony, and video-conferencing.

During that time, Yedwab said, manyof converged networks’ technical con-cerns will be addressed.

According to Lucent’s Meyers, the keywill be switches and routers graduallybecoming faster, less expensive, and bet-ter able to handle more media types.

Said Yedwab, “We’re going to be see-ing lots of things happening over the nextthree years that will enable convergednetworks to really start taking off.” ❖

John Edwards is a freelance technologywriter based in Gilbert, Arizona. ContactEdwards at jedwards@john-edwards.com.

Industry Trends

The forces driving the movementtoward converged networks includeincreased competition between telecom-munications carriers, causing them tolook for savings, efficiencies, and othermarketing advantages; the widespreadadoption of digital technologies; andfaster transmission capabilities.

UsersBusinesses hope network convergence

will solve several costly telecommunica-tions problems. Most critically, the tech-nology eliminates the need to spend timeand money operating, managing, andmaintaining separate voice and datanetworks.

This also simplifies vendor relation-ships, said Jay Pultz, a Gartner Groupvice president and research director.

In addition, businesses can takeadvantage of reduced equipment costs,said Michael Speyer, associate directorof the Yankee Group, a technologyresearch firm. He explained, “They cansave the hassle of having a separate PBX(private branch exchange) system andlocal area network.”

For very large organizations, a keybenefit of network convergence is the

option of using their private telecom-munications links to bypass the publictelephone network. This approach cancut expenses by letting companies makefuller use of their own networks and alsoeliminate service-provider-related costs,Pultz said.

Meanwhile, use of a converged net-work can give small businesses many ofthe same telecommunications capabili-ties—including continuous high-speedInternet access, real-time videoconfer-encing, and less expensive long-distancecalls via the Internet—as Fortune 500corporations.

SuppliersThe Telecommunications Act of 1996

opened the door to increased competi-tion between traditional telecommuni-cations carriers, such as AT&T andNorthern Telecom.

These carriers have been encouragedto compete by offering more than justtraditional voice services, primarilybecause there has been a huge increasein data traffic. Speyer noted that datanetworking is currently growing 13 to14 percent annually.

Meanwhile, a new generation of start-

up carriers, such as Level 3 Communi-cations and Qwest Communications, arebuilding their own all-IP networks tocompete against traditional providers andtheir legacy circuit-switched systems.

Carriers have generally found thatthey can appeal to customers by offer-ing the convenience of an array oftelecommunications services providedvia a single converged network. This canalso be less expensive for companiesthan buying services individually frommultiple vendors.

Networks standardize on IPOne of the major technological dri-

vers behind network convergence is theongoing standardization of networks onIP. With data and voice running over IP,it is easier to handle both in a convergednetwork.

“IP networks have rapidly become acritical part of the industry,” said RichKlapman, product director for AT&T’sintegrated networks business. “And it isonly going to become more important.”

The standardization on IP is occurringbecause of packet technology’s efficiencyand because it lets network users exploitInternet technology, such as browsers.

The Forces Driving Convergence