HerryLBoscoMlcII8eI J. Stef8nlk

Peter H. Stuntebeck

A Broad Path for Network Migration:BISDN Products and Services from ATaT

The ultimate goal ofAT&Ts strategy for broadband products and services­an integrated communications infrastructure thatwill make multimedia com­munications as ubiquitous and easy touseas traditional telephone service­may be revolutionary in itseffects oncommerce, education, health care,entertainment, and many aspects ofeveryday life. But evolution, not revolu­tion, is the path to thatgoal. Together with itsleadership inasynchronoustransfer mode (ATM) technology, the cornerstone ofmultimedia networking,AT&T offers realistic, flexible options for the evolution oftoday's hetero­geneous networks-whetherprivate or public, optimized for data, voice, orvideo-towarda future technology infrastructure ofbroadband integratedservices digital networks (BISONs) based onATM. Insurveying some ofthemajor product and service plans ofAT&T Network Systems Group (NSG)and AT&T Communications Services Group (CSG) , thispaper presents abroad evolutionary path for migration to BISON.Introduction

Broadband ISDN basedon ATM is apartofthe technological underpinning com­monto several ofAT&Ts strategic initiatives.Forexample, both high-bandwidth transportand service integration are keycapabilities forthe initiative inscalable computing, whichcombines opensystemsand networking tech­nology to provide enterprise-wide solutions.Someaspectsofthe initiatives in datacom­munications and in multimedia messagingrequirethe samecapabilities. And evolutionto BISON is essential to the fruition ofthevisual andmultimedia communications initia­tive-a drive to enable inexpensive videocommunications, a rangeofinteractive multi­mediaservices, andhigh-definition television- no less essential thanAT&Ts leadershipin digital video compression technology.

With the aimofproviding notonlythe long-range vision but alsoa broadpathforthe gradualmigration oftoday's networkstoward BISON/ATM, AT&T has creatednewinternal organizations andforged externalalliances that focus on this technology. AT&TNetwork Systems Group has pooled its primecompetencies from its switching, transmis-

sion, anddatanetworking experience todesign an ATM-based product lineto meettheneeds ofend users and service providers. Acomplementary thrust within AT&T Commu­nications Services Group (CSG) has createdaneworganization to plan and implement amultimedia broadband network to offer multi­media services to business customers.AT&T-CSG is joining forces with newindustrypartnersto address the near-future needsofthe marketforhigh-bandwidth connectivityand service offerings.

Network Systems Group: An Integratedservices Approach

AT&T Network Systems Group hasintroduced a set ofproducts, designed withevolution in mind, which can meetcustomers'needswithout jeopardizing their networkinvestment. The GlobeView-200()fM Broad­bandSystem offers the elements neededtointegrate the combination ofdata, images,video, andvoice that will characterize com­munications traffic on the information super­highway. Amodular digital system basedon advanced cell-relay technology, theGlobeView-2000 Broadband System can

76 AT&TTECHNICALJOURNAL. NOVEMBER/DECEMBER 1993

synthesize the elements in today's switching andtrans­mission systemenvironments.

The heart ofthe GlobeView-2000 System is itshigh-capacity, modular Service Node. Thiscentral ele­mentofthe systemconsists ofa high-performance ATMswitching fabric, numerous network interfaces, andalocal fault-tolerant controller. The switching fabric, whichis the switching anddata-storage coreofthe ServiceNode, servesas a shared memory, with a portbuffer thatis sharedamong multiple ports. Patented byAT&T, thisswitching fabric offers highly efficient datastorage, excep­tionally highreliability, andunmatched performance.

Depending on customer needs,the ServiceNode canbe configured with a capacity of2.4 or 20giga­bitsper second (Gbits/s),with multiple priorities forcelllossand delay. AT&Ts implementation ofthe shared­memory designmakesthe system extremely robustandensures that combinations ofburstypacketdatatrafficandcircuit-oriented traffic canbe carriedat peakrateswithout degradation in performance. The modular designofthe shared-memory switching fabric allows expansionbeyond 80Gbits/s.

The 2.4-Gbits/s configuration ofa Service Nodeoffers a low-eost alternative to enable service providers'entryintothe high-speed dataapplications market. Usingthisconfiguration, innovative service providers candeploy a modular andcell-based accessplatform at theedge ofthe network, offering revenue-generating ser­vices to "earlyadopter" customers. The 2.4 Gbits/s con­figuration employs the samerobustswitching fabric andintegrated network management features ofthe high­capacity Service Node 2()'Gbits/s configuration. Asdemand forhigh-speed and multimedia services grows,investment in the Service Node 2.4 Gbits/s systemisprotected. To meetgrowing needs, the systemcanbeeasily upgraded with additional switching capacity. It canalso be integrated with networks that are currently pro­viding SMDS andframe-relay services.

Forbusinesses that depend on information trans­fers, network reliability andperformance are critical. Inthe Service Node, allelements that affect service areduplicated, including the shared-memory fabric andthenodecontroller. This design ensuresthat service willcontinue regardless ofanysystemproblems.

The Service Node can support multiple circuitpacks with various types offunctions, interfaces, andpro­tocols, including ATM user-network interfaces (UNIs)

Figure 1. This service Node fabric cabinet houses theGlobeVlew·2000 System's shared-memory fabric andInterface cards.

andnetwork-network interfaces (NNIs), high-speedinterfaces-includingDS3/E3, sra.i/re, SfM-4, OC-3, OC-12,andOC-48-as well as multimedia bridges, video servers,anddataservers.

The module responsible forintegrated networkmanagement in the GlobeView-2000 System is the Ser­vice Management Module. It offers an intuitive, custom­izable graphical user interface with advanced open­systems, object-oriented software and is basedonTele­communications Management Network (TMN) standardsforoperations, administration, maintenance, and provi­sioning. In addition to comprehensive management fortheGlobeView-2000 System, this module provides fault toler­ancethat is scalable according to network size andneeds.

The Service Management Module offers a rangeoftraffic profile options thatgo beyond the policingparameters defined bythe ATM Forum. Traffic policing isimplemented usinga virtual scheduling algorithm, whichenables the service provider to allocate andmanage theService Node bandwidth ina cost-effective manner. Basedon the UNIX® operating system andthe BaseWorX™applications platform, the Service Management Module

AT&TTECHNICALJOURNAL. NOVEMBER/DECEMBER 1993 77

Figure 2. The GlobeVlew-2000 Service Management Modulemakes provisioning functions accessible through an easy-to­use, polnt-and-cllck graphical user Interface.

offers standard interfaces to local exchange carriers'operations support systems.

The Service Management Module canbe locatedwith a Service Node or at a remotesite. Fora local Ser­vice Node, a Maintenance Module workstation providesspecial functions, suchas nodeinitialization and recov­ery; diskstorage, backup, and failure recovery; and localtroubleshooting. Alocal nodeis connected to either aMaintenance Module or to a Service Management Mod­ule,which can provide similar local functions as well asoverall network management.

The Access Module can be configured to provideaccessand supportformostmajor applications, includingdata networking services, entertainment video, andcost­effective network infrastructure solutions forATM andSTM in both synchronous optical network (SONET) andsynchronous digital hierarchy (SOH) environments. Avideo multiplexer will terminate SONET OC3c channelsand perform MPEG2 transportstreammultiplexing forefficient distribution ofentertainment video services.

The Switched Services Module supplies real­timecall processing, signaling, andcontrol for BISON.This module offers rapid deployment ofswitched ser­vices, accessto a full rangeofprovisioned services, andintegration with other intelligent network elements.Additional advantages include redundancy ofhardwareelements, fault-tolerant control, the ability to selectlevels

78 AT&TTECHNICALJOllRNAI.• NOVEMBER/IJECEMHER Hl!J:l

ofcapacity and service quality, and real-time statusupdates. In the future, switched services will makeit aseasyfora casual user to set up a multimedia call as it isto makea telephone call today.

A Portfolio of System Configuration.The GlobeView-2000 portfolio enables network

and service providers to combine systemmodules inconfigurations tailored forspecific types ofapplicationsand to deploy broadband andATM capabilities with maxi­mumeffectiveness. All three configurations-the ATMhigh-speed datasystemand services configurationknown as GCNS, the ATM bandwidth management systemand services configuration known as AXC, and the ATMsystemforswitched services known as Bss-fit smoothlyintoexisting networks.

In keeping with the goalsofthe GlobeView-2000System, allconfigurations are designed to preserve andextendthe value ofcurrent network investments whileallowing the simultaneous development ofnewservicesand capabilities. Theyallow the modular elements oftheGlobeView-2000 System to be used as required to meetthe needs ofnetwork operators and service providersaround the world.

With the GlobeView-2000 System, allfunctional­itycanremain in place indefinitely or canevolve as thenetwork evolves. In other words, functionality is notreplaced, but enhanced, whenandwherethe needsofthe service provider requireit. Unified OAM&P, ease ofservice creation, andthe best-in-elass technology are thequalities embodied in thisAT&T product offering. Itsevolutionary approach enables the rapid deployment ofnewservices ina flexible andcost-effective manner. Forexample, the Switched Services Module canbe easilyaddedto an existing GCNS or AXC andnetworked toenhanceservice capabilities. This allows service provid­ers to offer permanent virtual circuits (rvcs) today andamigration path to switched virtual circuits (svcs) withoutcompromising their investments.

Communications Service. Group: Planned EvolutionToguidetoday's customers ontothe evolution­

ary path to BISON, AT&T-CSG plans to enhance its Inter­Span"services network to offer frame-relay services onATM, as well as native ATM dataservices. Atthe sametime, AT&T-CSG is deploying a newinfrastructure net­work to provide future multimedia services.

AT&T-CSG is establishing strategicalliances andpartnerships to implement and provide earlyBISDN/ATMservices. AT&T-CSG and its industry partnersconsiderATM to be the fundamental technology for providingfuture high-speed, multimedia capabilities to users' local­andwide-area networks. Asin the approach takenbyAT&T-NSG, ATM implementation will be through an evolu­tionary processproviding investment protection forcus­tomersand a smoothtransition, which will allow themigration ofindividual customerlocations to ATM at a pacethat is consistent with the customer'sbusinessneeds.

AT&T-cSG and its partnersare cooperating onthe definition ofstandardsand the specifications ofprod­ucts and services to supportATM. The firstarea ofcollab­oration will be ATM-to-frame relay interworking, whichwill provide connectivity amongframe-relay devices,native ATM devices, and an ATM wide-area network.AT&T-CSG and its partnersrecognize ATM-to-frame relayinterworking as a keycomponent in the developmentpath to BISDN/ATM, and havebegunworking to specify,develop, and deliver this capability. ATM-to-frame relayinterworking will permitusers to continue deployingframe relay todaywithout fear that their investments willbecome obsolete. Userswill be ableto add ATM connec­tionsto existing enterprisenetworks when and wheretheyare justified. AT&T-cSG views ATM networking as anatural andgraceful extension ofthe InterSpan FrameRelay Service.

Frame-relay services will be provided in a multi­bandenvironment, with sufficient speedand bandwidthsavailable foreveryapplication - from low-speed datathrough high-speed data. The fully evolved AT&T-CSGnetwork will employ core ATM switching provided byAT&T Network Systems. AT&T and its partnerswill pro­vide narrowband andbroadband cell-relay switches withATM andframe-relay capabilities. AT&T NCR will inte­grate ATM technology intothe endpoint and intermediatesystemrouters and bridges. AT&T NCR andAT&T Para­dyne will provide the premisesequipment. AT&T-CSGwill integrate these technologies and provide end-to-endATM network services andATM-to-frame relay network­ing. AT&T Global Business Communications Systems(GBCS) will further enhancethe capabilities ofits PBXsto manage multimedia, voice, video, and data traffic.

The migration to BISDN is expected to start withhigher bandwidths forexisting services, accompanied bynewerservices that allow multipoint and multiconnection

communication. Additional work is in progressto finalizethe standardsfor newservices, as well as forvoice andvideo supportoverATM. Some ofthe technical issuesfac­ingsuch services, including echocancellation, jitter, andsynchronization between voice andvideo signals, haveyet to be resolved. Nonetheless, to meet the needsofthemarket, AT&T-CSG is planning to implement a Multime­diaBroadband Network (MMBN).

Due to a remarkable convergence ofenablingtechnologies, the voice/e-mail/fax "call oftoday" willevolve to become the "multimedia call ofthe future."This multimedia call combines voice, video, image, text,data, and animation. Many companies believe multimediawill become the core communications vehicle oftheirfirms. MMBN, usinga newtechnology infrastructure, willsupport the multimedia call ofthe future. MMBN serviceswill be based on an ATM platform that utilizes SONETtransmission.

A Survey of MMBNServicesMultimedia Virtual Network (MVN) service

allows AT&T to offer its businesscustomers multimediacall functions andcapabilities equivalent to thoseofa pri­vatenetwork without requiring dedicated resources. Thetimesharingofnetwork resources ina Multimedia Vir­tualNetwork results in overall savings due to the moreefficient usageoffacilities, the benefits ofthe combinedengineering offacilities, and the economies ofscale.These savings allow AT&T to offer MVN services at ratesthat are economically attractive tocustomers, with newrevenue opportunities and a marketalternative to privatenetwork offerings. The MVN approach alsofacilitatesmaintenance ofnetwork operations.

Multimedia Virtual Network service providesusers with simplified dialing among themselves via a pri­vatenumbering plan, and increased privacy incommuni­cations viaappropriate blocking ofcalls. In addition, MVNservice has the following potential benefits for the sub­scribing customer:- reducedcost ofservice throughvolume discounts

depending on the traffic committed to the MVN,- increased flexibility in the configuration and

reconfiguration ofthe MVN via a centraloperatingpoint, which can be operated by the customerusingaservice-ereation environment, and

- customized billing arrangements that include call­detail reporting.

AT&TTECHNICAL]OURNAL. NOVEMBER/IlECEMBER 1!~1:l 79

Voice only

To existingnetworks

Multimedia

Datil only

ATMLANhub-

rn-oca

Integratedaccess

T45

111

1 11- .. -- ....-;---- 1

im:,:,me,,'nt,',+------- ..'I~,.l ...

650 Mbitsjs

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Figure 3. The Multimedia Broadband Network (MMBN) Is ageneral architecture that offers a variety of types of access,and Interaction with a variety of Intelligent networking ser­vices, based on ATM switching and SONET transmission.

Service featuresprovided by MVN-suchas a pri­vatenumberingplan, off-net calling, authorization codes,selective barring,and variable routing-apply to multi­mediaor single-medium callsincluding voice, video, anddata.These featurescan be assigned line-by-line to users

on the basis ofE.164 numbers identifying individual lines.Virtual MeetingService (VMS) is the equivalent

ofconference calling in the voice environment, aug­mented to supportmultimedia connections. The VMS pro­videsa meetingenvironment similar to real face-to-facemeetings. Basedon a multimedia desktopconferencingsystem,VMS allows a group ofpeople to hold real-timediscussions in whichthey share voice, video, and datainformation over longdistances. VMS provides call­management mechanisms for its users and coordinates

80 AT&TTECHNICALJOURNAL. NOVEMBER/DECEMBER 1993

communications invarious media duringconferences.Participants canbe added, dropped, or placed on holdduringa conference. VMS can manage conferences witha mixofdevices, including bothcomputers and tele­phones. Conference participants with appropriate moni­tors may see eachother andalsoshare displays ofvisualinformation. Computer programs associated with VMSconferences produce identical displays on the computerscreensofconference participants. Conference partici­pantswith conventional telephones canjointhe confer­ence,sendingand receiving only the voice signals.

Aspects ofanotherMMBN service, known as Uni­versal Messaging, already exist in the form ofvoice mailandelectronic mail. The newingredient that completesthis service isvideo mail. Universal Messaging Serviceallows users to leave video messagesforeach other,including computer dataand images. The Universal Mes­sagingService includes a database wheresubscriberswill have a binconsisting ofa certain amount ofmemorypredetermined upon subscription. The memory sizedetermines the maximum lengthofstoredvideo mes­sages and the numberand resolution ofstoredimages.The subscriber's bin is accessible viaaccesscodesandpersonal identification numbers (PINS). Messages canberouted to this database on the basisofa numberofcondi­tionsthat mightexistat the timeofan incoming multime­diacall. The callermay chooseto place a multimedia callin the called party'sbinwith a timestampto be deliveredat a specific timein the future. Underanyconditions trig­geringUniversal Messaging Service, the user should beinformed aboutthe presence ofa multimedia messageviaeitheran audio or visual indication, depending onthetype ofterminal equipment used.

Multimedia 800 Service extendsthe voice 800services to include multimedia calls. Initial Multimedia800 services offered by MMBN will be less numerous andcomplex than current 800 services. Theywill includecallsthat are toll-free to the calling party, wherethe sub­scriberis billed a feebasedon expected usage in termsoftraffic, calling areas,and quality ofservice. Also, theywill offer variable routing, inwhich incoming callscan berouted to different destinations nationwide on the basisoftime ofday, dayofweek, holidays, andcalling partynumberidentification. Calls canbe single-medium(including voice, data, or video) or multimedia.

Customer Network Management Services allowthe service subscriberto control and manage the differ-

ent services andfeatures available to its multimedia sta­tions. In the contextofMVN, the service subscriber canassignfeatures that are partofthe MVN service to indi­vidual stations. These assignments canbe updated asneeded. The subscriberwill haveaccessto an opera­tionsand management center that provides on-line pro­visioning ofservices andtrouble-tracking capabilities.Traditional network-management functions, such as test­ingand loopback, fault detection and isolation, andauto­matic restoration, are alsoprovided to the customer.Network modeling, capacity planning, andservice cus­tomization viaa user-friendly service creation environ­mentare alsosupported.

Finally, because it cannotexistin isolation fromthe presentvoice networks, MMBN is designed to inter­workwith them in supporting voice services. UsersatMMBN stations mustbe ableto communicate with usersservedby the current public switched telephone net­works. Voice equipment, suchas that used to provideechocancellation, tones, andannouncements, will besupported. Currentvoice services are numerous and willnotbe allsupported in the initial implementation oftheMMBN; however, the voice services that are mostwidelyusedwill be supported. Services suchas Call Forward­ing, Call Transfer, Incoming Call Indication, Three-WayCalling, Call Hold, Call Pickup, Calling Card Service, Col­lectCalls, andThird Number Billing will be available,and notforvoice callsalone. These services will alsoapply to multimedia callswhenappropriate.

A Commltlll8llt to the CustomerThe NSG and CSG product and service offerings

surveyed here do notbyanymeansrepresentAT&Tstotal contribution to ATM. Theydo,however, plainly illus­trateAT&Ts commitment to a broad, evolutionary pathcapable ofaccommodating diverse customer needs. Theyalsodemonstrate AT&Ts understanding that the com­petitiveness ofanycustomer's enterprise dependsequally on preserving the value ofpresentinvestment,introducing newcapabilities ina timely manner, andbuilding the advanced technological baseit will need tocompete successfully in the future.

Acknowl......-.uThis paperis basedon the work ofmany ofour

colleagues at AT&T. In particular, the authorswish toacknowledge the following people fortheir significant

AT&TTECHNICALJOURNAL. NOVEMBER/DECEMBER 1993 81

contributions: Susan Friedman and Roger Levy ofAT&Ts ATM Platform Organization; ArefMatin, ofAT&Ts Business Communications Services BusinessUnit; andAbdallah Saleh ofthe AT&T Architecture Area.

Harry L. Bosco is the ATM Platform Organization Vice Presi­dent in AT&T Network Systems, Red Bank, N.J. Mr. Boscobegan his AT&T career in 1965 in the Data Communicationsarea of Bell Labs. His responsibilities have included designand overall project man~gement for the 5ESS switching sys­tem, operations systems development, and product manage­ment for medical systems. He was appointed Data NetworkingVice President in 1989 and assumed his current assignmentin 1992. Mr. Bosco received an A.SEE. degree from Pennsyl­vania State University, a B.S.EE from Monmouth College,and an M.S.E.E. from the Polytechnic Institute of New York.Michael J. Stefanik is head of the Next Generation NetworkArchitecture Department at AT&T Bell Laboratories inHolmdel, N.J., responsible for specifying intelligent networkand broadband network architectures. Since joining Bell Labs

112 AT&r TECHNICAL )Ol'RNAL. NOVEMBERIJ>ECEMBER 1993

in 1973, he has held a variety of positions in switching sys­tems engineering, network planning, and technical field sup­port, and has led standards groups responsible for aspects ofthe analog-to-digital transition and ISDN. He has a B.S.EEdegree from Valparaiso University and M.S and Ph.D. degreesin electrical engineering from Ohio University.Peter H. Stuntebeck is the division manager of Next Genera­tion Services and Technology Planning in AT&T Business Com­munications Services, Middletown, N.J. His organization isresponsible for business and technology planning based on athree- to ten-year view of customer needs and emerging tech­nologies. Mr. Stuntebeck's career in AT&T began at Bell Labsin 1973. His assignments have focused on performanceanalysis, network planning, and advanced service conceptsand architectures. He received a B.S. degree in physics fromThomas Moore and M.S. and Ph.D. degrees in physics fromNotre Dame.