What's SIP Got to Do with It?

What’sSIPGotToDoWithIt?

FiveCompellingReasonsWhySIPWillDominateEnterpriseIPTelephony

WHITEPAPER

CONTENTS

Introduction...... 1

RecentLANandWANtechnologies

makevoicesoundgood...... 1

2005—YearofVoIP...... 1

TheImportanceofSessionInitiation

ProtocolinEnterpriseIPTelephony...... 2

SIPissimple...... 2

SIPissecure...... 2

SIPisastandard...... 3

SIPapplicationsabound...... 3

SIPisusedbyenterprises

andcarriers...... 3

Summary...... 4

Introduction

RecentLANandWANtechnologies makevoicesoundgood.

Since1998when3Combroughttomarket thefirstIPPBX,theenterpriseVoiceover

IP(VoIP)phenomenon has changednotjust telecommunications,butalsoenterprise networking.The 3Com® NBX® system usheredinanew era ofcommunications.

Forthefirst time,companieswereableto leveragetheirinvestmentsinhighperform- ancelocalareanetworks(LANs)todeliver real-time services suchasIPtelephony.

Infact,themajorstandardizedinnovations inLayer2switchesandenterpriserouters inthepastfiveyears—virtualLAN(VLAN) segmentation,packetprioritization,Power overEthernet(PoE),differentiated services,

multi-protocollabelswitching—enhance convergednetworkinganditsdeliveryof high-qualityaudio.

•VLANsegmentationseparatesvoice trafficfrome-mailuploads,websurfing, anddatabaseinteractions

•Packetprioritizationtechniques enable higherpriorityforvoicepacketsthan otherapplicationssothatjitterand delay areminimizedor eliminated

•PoE enables acombinationpower-and- communicationscabletominimizethe requirednumberof120Vpowerports

•Differentiated services andMulti- ProtocolLabelSwitching(MPLS) enable prioritizationforvoicepacketstreams andrapidtransit acrossIPwidearea networks(WANs)

EnhancementstothewirelessLANenvi- ronmentthroughthe auspices oftheIEEE

802.11committeesalsofacilitate high qualityIPtelephony services.Recently

ratifiedspecificationsfor Quality ofService overtheair(802.11e)andprivacy services (802.11i)addressmanyofthesameissues beingaddressedbyother802.1committees.

Technologyadvancesaredrivingsignificant

investmentinthedevelopmentanddeploy- mentofmorereliableandhigh-performance LANs.This momentumhelpsmaximizethe reliabilityandaudioqualityofIPtelephony implementationsandcreatesolutionsto matchthecostexpectationsofenterprises.

2005—theYearofVoIP

2005isafundamentalturningpointforthe IPtelephonyindustry.Forthefirst time, moreIP-PBXports will shipintheUnited Statesthanlegacydigitalports.This isa majormilestone,indicativeofthereliability andaudioqualitynowavailableinIP telephony services.The discussion of“if” users will migratetoIPtelephonyisnow “when”andwithwhatstrategicurgency.

Classically,theyear ofinflectionrepresents an acceleration ofthepaceofgrowthinthe market.InthecaseofIPtelephony,this accelerated growthisoccurringnowfor

twoprimaryreasons:

•Depreciation schedules—equipment purchased inpreparationforY2Kisbeing retirednow, enablingnewpurchases

•Largeenterpriseneeds—emergingbusi- nessrequirements necessitate enhanced, cost-effectives services,alreadyenjoyed bysmall businesses withIPtelephony deployments

The value propositionforIPtelephonyis movingbeyondcostreduction-oriented businesscases,toaframeworkof“conver- gence applications”thatofferadvantages difficulttoaccomplishwithlegacytelephone implementations.Applications—suchasIP messaging—canbroadcast voicemailand delivervoicemailase-mail.IPconferencing can provideaudio,video,anddataconfer- encing services.IPcontactcentersoffer freedomfromthegeographicconstraintsof legacysolutions.IPmobilitysolutionsthat provideon-campusvoiceanddataservices

viawirelessLANsareprovingthemselves criticalforbusinessproductivityand customerinteractions.

1

3COM® WHAT’S SIP GOT TO DO WITH IT? WHITE PAPER

SessionInitiationProtocol(SIP)

SIPwasdeveloped in 1999 asamediaand applicationindependentsessioncontrol protocolbytheInternetEngineeringTaskForce, thesamepeopleandprocessdevelopersthat manageallimportantInternet protocolslike

IP, FTP, TLS,andHTTP. SIPisdenotedasRFC

3261, which definesthemessages,options, and protocolsattheheartofSIP.

Learn more at:

or

TheImportanceofSession

InitiationProtocolin

EnterpriseIPTelephony

Ifindeedapplicationsarethedrivingforce behindIPtelephonyimplementations,what will bethekey enablerofenterpriseapplica- tions,enterpriseapplicationsdevelopers,

andintegrationsintoexistingenterprise applications?

Itisthepremiseofthiswhitepaperthat SessionInitiationProtocol(SIP)willfillthat need.

SIPissimple.

UsingtheInternetEngineeringTask Force (IETF)fundamentaloftechnologyreuseand theprovenvalueofsimplicity,theSIPmessage setisquiteanelegantconstruction—six messagesthatappearincleartexttofacili- tatecallsetup.Cleartextallowsforeasy troubleshootingandavoids complexsoft- wareinteractionsandotherprocessingthat affectinteroperability.The sixmessagesare Invite,Trying, Ringing,OK,ACK,Bye.

SIPisbothelegantandpractical.Itsbase assumptionisthatallSIPendpointsand elementsexistintheIPenvironment,an

arena alreadyequippedwithstandardmech- anismstohandlepackettransportpriorities, privacy,andotherrequired services.These value-added services donotrequirespecifi- cationintheSIPframework.Whereas,in legacyenvironmentssuchasthepublictele- phonenetworktheuseofhyper-texttransport protocol(http)isneitherintegralorreadily available.

This “buildingblock”approachonanIP

baseisuniquetoIETFinitiatives.Theresults arenearlytrivialprotocoldefinitionssuchas SIPincontrastwitholdersessioncontrolor interfaceprotocolssuchasH.323orQ.SIG

fromtheInternationalTelecommunications Union(ITU).Theseolder, telecom-centric protocolshave considerablymorecomplex definitionsas showninTable 1.

In civilization andinnature,simple has

beenproventobebothusefulandenduring. Forexample,thesphereanditsderivatives

arefrequentlyoccurring shapes infruitand celestial objects ascontrastedtothemore complexpyramid.The steeringwheel,rather thanthehandlebar,isusedin automobile controldesigns.The flatCDreplaced the

morecomplexfloppydiskcartridgedesignas thedefinitivemedia storageframework.

Yearsago,awisemanonceexplainedwhy AsynchronousTransferMode(ATM)was goingtodestroyacarrierserviceofinterestto thephonecompaniesatthe time—Switched Multi-megabitDataService(SMDS)—that

wasa connectionless ATM-typeservice.Two argumentsweregivenforhisassertion.First, ATMwassimpler(noticethree-letteracronym versusthefour-letter acronym).Second,

ATMdidn’trequireaphone companyto implementthetechnology,resultinginATM havingalargeraddressablemarketthat

couldprovideampleopportunityforsolving businessproblems(relevance).

SIPissecure.

Therearetradeoffsbetween interoperability andcostwhenconsideringsecurity.Simple standardsmakeiteasiertointeroperatewithin

amulti-vendornetwork,buttheyalsoexpose thenetworktopotentialabuse.This vulner- ability,however, can beeffectivelyaddressed bystrongauthenticationandprivacyservices. thatdonotinterferewiththeprimarybusi- nessbenefitofstandard-basedsolutionsand also enablea long investmentlifethrough interchangeablevendors, services,applica- tions,and devices.

The IETFframeworkforSIPoffersarichset ofstandardsforauthenticationandprivacy, includingsecureSIP,secureRTCP,andsecure RTP.ThesecapabilitiesleverageIETFproposals forthe use ofstandardimplementationssuch asTransportLayerSecurity(TLS)forrobust

sessionprivacy service andSecure/Multi- partInternetMail Extensions (S/MIME)for sessioncontrolpacketprivacy.

TABLE 1: Contrast between key SIP attributes and H.323 signaling protocols.

[Source: Business Communications Review, October 2004]

ATTRIBUTEH.323SIP

3COM® WHAT’S SIP GOT TO DO WITH IT? WHITE PAPER

MostvendorsimplementingH.323offerno

suchoptions.Instead,theychoosetoimple- mentproprietaryderivativestofacilitate rudimentaryformsofprivacyinfirstgener- ationIP-PBX devices.This approachis

typicalofthePBXvendorsolutionsbrought tomarketduringthepasttwodecadesin whichproprietarydigitalsignalingprotocols wereimplementedonendpointsandPBX fabric.The resultofthesedecisionswas nominally-bettersecurity,but considerably morevendor-specific lock-in thatfailedto providemanyusefulfeatures—suchascall forwardandhold—atastandardservicelevel.

SIPisastandard.

Despitebeingastandard,SIPimplementa- tionsdovary.Somevendors,mostnotably legacyTDM-basedPBXvendorsandfirst generationIPtelephonyvendorswhobuilt theirproductsaroundH.323oraround proprietaryprotocols,offerSIPinteroper- abilityasaninterfaceintotheirotherwise non-SIPtelephonysystem.This approach helpsthevendormaintainaccountand featurecontrol.They can chargeextrafor SIPsupportforonlythemostrudimentary featureswhile offeringadvancedpremium-

pricedfeatureoptionswiththeirproprietary callcontrolprotocolandimplementation.

AloneamongtheleadingIP-PBXvendors,

3Com has implementedadifferentapproach. UsingstandardSIPamongendpointssuchas IPphones,videocameras,callcontrollers

and gatewaystothepublictelephonenetwork,

3ComSIP-basedsolutions enablearobust

andinexpensive,vendor-neutralenvironment, capableofrapidlydeliveringaportfolioof cutting-edgeapplicationsforpresence,confer- encing,contactcenter,messaging,and mobility services.Furthermore,3Comisa foundingmemberoftheSIPForumand promotesthe3ComVoiceSolutionsProvider

ProgramasaninitiativetoencourageSIP-

basedinteroperability.Alistofmorethan30

vendors, service providers,andsolutions thatareproventointeroperatewith3ComIP telephonymodulesisavailableat:

SIPapplicationsabound.

Internetsearchengines can beanamazing proxyformarketsandissues.Theirobjective istoscourtheInternet,captureprose,process

whatevertheyfind,andquicklypresentit touserswithsomerankorderingthat approximates users’viewsofrelevancy.

Google, inparticular,isaneffectivemeasure of”buzz” because ofitscontentpresentation intermsofusers’viewsofrelevancy.

Figure2 showsthecontrastbetween the numberofreferencesfoundbytheGoogle searchenginefor“SIPapplications”,“H.323 applications”,and“CiscoSkinnyCallControl Protocol.”Inthis analysis,thepresenceof open,simple(SIP)referencesclearlyout- pacesreferencesforopen,complex(H.323) andproprietaryapplications. End usersare recognizingthe enormous flexibilityand value ofSIP.

SIPisusedbyenterprisesandcarriers. SinceSIPtranscendscarrier/enterprise boundaries,it can attractapplicationsdevel- opersabletodelivertheir coreapplications

technologiesinavarietyofvalue packages

andtoaddressarangeoffinancingmodels andmarkets.Forexample:

•The stand-aloneenterprisemarket, addressedbydirectsalesorresellers

•Thestand-aloneconsumermarket,addressed byretailers,onlineordirectmarketers

•The hostedservice model, sold tocarriers butbilledtoenterprisesinmonthlycharges

FIGURE 2: Thousands of references on Google.com, January 2005.

1400

1200

1000

800

600

400

200

0

SIPApplicationsH.323 ApplicationsSkinny Call Control

ProtocolApplications

3

3COM® WHAT’S SIP GOT TO DO WITH IT? WHITE PAPER

3Comhasbeenamajorcontributortothe convergenceindustrysinceit broughtto markettheNBXIP-PBX in 1998. It developed anarchitectureforadistributedsoftswitchfor AT&Tandintroducedit in the first commer- ciallydeployedcarriersoftswitch in 1999. Then in 2003, the3ComVCX™ solution becameakeycomponentoftheworld’s first convergenceapplicationssuite. Maintaining itsleadershipposition,thecompanyisalsoa

foundingmemberoftheVoIPSecurityAlliance.

Transformingbusinessthrough innovationis notnewto3Com.Itholdsover1,600patents andisthemarketleader in IPtelephonyfor smalltomediumenterprises. It operates in over 45 countrieswithapproximately 1,900 employees.

3Com:we’rechangingthe waybusinessspeaks.

•The hostedservice model, sold tocarriers

butbilledtoconsumersinmonthlycharges

•The stand-aloneenterprisemarket, addressedbycarrierenterpriseequipment salesorganizations

This multi-marketmodelprovidesample spaceforinitialfocus.Dependingonvendor strengthsandskills,themodelsupports considerableopportunityforbothstartup and establisheddevelopers.

SinceSIPisusedbyenterprisesandcarriers acrossmultiplemarkets,carriers can offer innovative services aimedatenterprises.For example,SIPtrunking services allowtwo

SIP-empoweredenterprisestocommunicate usingRTPfromendpointtoendpointwithout theneedforagatewaybetween them.The growthofthis categoryof services ishelping reducecostsbyloweringtheloadonpacket- circuitgatewaysandreducingregulatory

andtaxburdens.

SIPtrunkingalsoimprovesaudioquality sincebandwidthallocationcanbenegotiated end-to-endinsteadofend-to-gateway-over- digital-to-gateway-to-end.Fewerdigital

hopswithmorebandwidth enables wide- bandaudioquality,aswellas SIP-initiated videoconferencing.

Summary

AsdemandforIPtelephonyandSIPservices andimplementationscontinues toaccelerate, thepublictelephonenetworkfaceschange.

A mainstayoftheglobaleconomyforthe pastten decades,itislosinggroundtoa networkofworld-wideIPcommunications integratedwithsimple,secure,standards- based,applications-richimplementations and services.

Therecanbelittledoubtoftheimportantrole thatSIPwillplayinfacilitatingthistransition andenablingpowerfulenterpriseapplications thatreducecost,improveuserproductivity, andstrengthen customerinteractions.Some vendors will beslowtoappreciateandtake advantageofthisopportunity.Theymayfocus theirenergiesonattemptingtoretrainthe transitionratherthanexploringitspossibilities.

3Comembracesinnovationandstandards. Theyareafoundationonwhichthecompany buildsbusiness-enhancingsolutions.The questionisnolongerwhy,butwhenwillSIP beintegraltoeverybusiness’future?

3ComCorporation,CorporateHeadquarters,350CampusDrive,Marlborough,MA 01752-3064

Tolearnmoreabout3Comsolutions,visit

Copyright©20053ComCorporation.Allrightsreserved.3Com,the3ComlogoandNBXareregisteredtrademarksof3Com Corporation.VCXisatrademarkof3ComCorporation.Allothercompanyandproductnamesmaybetrademarksoftheirrespective companies.Whileeveryeffortismadetoensuretheinformationgivenisaccurate,3Comdoesnotacceptliabilityforanyerrorsor mistakeswhichmayarise.Specificationsandotherinformationinthisdocumentmaybesubjecttochangewithoutnotice.

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