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Key Benefits for Maximizing VoIP Performance
• Wire-speedswitchingandroutingperformance
• Non-blockingarchitecture
• Lowlatency
• Lowjitter
Key Benefits for Maximizing VoIP Resiliency
• ExtremeXOS®-aconsistentoperatingsystemacrossallswitchingplatforms
• EthernetAutomaticProtectionSwitching(EAPS)protocolforcarrierclassLayer2resiliency
• ExtensibilitywithWidgetscriptingandtightintegrationofexternalapplicationsviaExtremeXOSInSite(XMLSDK)
Voice-over-IP (VoIP) Solution Overview
Businesseshavetraditionallymaintainedseparatevoiceanddatanetworks.Akeyreasonforthisisthatlegacynetworktechnologiescouldnotmeettheperformancerequirementsandvoicequalityneededtosupportreal-time,delay-sensitivevoicetraffic.Recentadvancesinnetworkingtechnology,suchastrafficprioritizationandbandwidthmanagementtools,havemadeitpossibletobuildeffectiveconvergedvoiceanddatanetworks.
Convergednetworksreducecostsbyeliminatingredundanthardware,communicationsfacilities,long-distancechargesandsupportstaffs,allwhileenablinganewgenerationofintegratedvoiceanddataapplications.Asaresult,convergednetworksreducenetworkcomplexityandimproveintegrationofdisparatebusinesssystems.
BypacketizingvoicetrafficintoIPpacketsfortransmissionoverdatanetworks,Voice-over-IP(VoIP)isbecomingakeytechnologyconsiderationformanysmallercompaniessearchingtolowercoststhroughtollbypassandlargerenterpriseslookingtotakeadvantageofconvergedvoiceanddataapplications.Withacomprehensivesuiteoftoolstomanageandensureintegrityofvoicetraffic,ExtremeNetworks®providesthemosteffectivenetworkinfrastructureforsupportingVoIPandotherconvergedapplications.Toensureabest-of-classVoIPsolution,ExtremeNetworkspartnerswithstrategicVoIPtechnologypartners.
BydeployingVoIP,companiescanoffloadinternalcorporatetelephonytrafficfromthePrivateSwitchedTelephoneNetwork(PSTN)ontothedatanetwork.VoIPcanalsobeusedtosupporte-commerceapplications(suchascallcenters),wherecriticalcustomeraccountinformationisbroughtuponthecomputerscreenduringcustomerservicephonecallsbysimplypunchinginacodeorpassword.
Deploying VoIP in the LAN and the WAN IPtelephonyintheLANrequiresseveralthingsfromthenetworkinfrastructure.Thetoptworequirementsarepredictableperformanceandaresilientnetworkdesign.WhileVoIPisnotabandwidth-intensiveapplication,itdoesrequirethatbandwidthalwaysbeavailable,voicetrafficbeidentifiedashighpriority,andthatQualityofService(QoS)bemaintainedbyminimizinglatency(delay)andjitter(delayvariation).
TelephoneusershaveveryhighexpectationsbecausetheyareaccustomedtotheQoSprovidedbythePublicSwitchedTelephoneNetwork(PSTN)andlegacyPrivateBranchExchange(PBX)basednetworks.Theseconnection-oriented,circuit-switchednetworksprovideeachuserwithdedicatedbandwidthforthedurationofeachcall.Theresultisextremelylowlatencyandjitter,andminimaldisruptiondueto“noise”ontheconnections,allowinguserstocarryonnaturalconversations.
© 2009 Extreme Networks, Inc. All rights reserved.
Extreme Networks Voice-over-IP (VoIP) Solution Overview
Extreme Networks Voice-over-IP (VoIP) Solution Overview
© 2009 Extreme Networks, Inc. All rights reserved. Extreme Networks Voice-over-IP (VoIP) Solution Overview—Page 2
bandwidthsfordifferenttypesoftraffic.Policiesaresetsofhigh-levelrulesthatdeterminehownetworkresourcesareallocatedtoapplications.BycreatingQoSpoliciesthatidentifytrafficgroupsanddefineQoSprofilesthatspecifythelevelofservicethatthosetrafficgroupsreceive,companiesutilizingPolicy-basedQoSareassuredthatintegrityofmission-criticalVoIPtrafficinrealtime,evenduringperiodsofnetworkcongestion.
AvailableonallExtremeNetworksswitches,rateshapingandDiffServareothertrafficmanagementandbandwidthprioritizationtoolsthatcanbeusedtosupportVoIPtraffic.BandwidthmanagementisperformedonthebasisofDiffServ(formerlyknownasIPTOS)codepoints.Witheighthardwarequeuesperport,theminimumandmaximumbandwidthparametersofeachqueuecanbemappedtoDiffServcodepointstoprovidetrafficprioritizationandrateshapingfordifferentclassesoftraffic.
Figure 1: Voice-over-IP (VoIP) in Action
Building the Right Infrastructure to Support VoIPOneofthekeychallengesinimplementingVoIPistodesignandbuildanIPbasednetworkthatmeetsstringentQoSrequirementsandiscomparableinperformancetoconventionalcircuit-switchedtelephonenetworks.Highlatencyforwardingandbest-effortdeliveryprovidedbytraditionalswitchesarenotacceptablefordelay-sensitivetrafficlikeVoIPbecauseitdoesnotprovidelatencyorbandwidthguarantees.FromtheperspectiveofanIP-basedEthernetnetwork,aVoIPpacketcontainingpartofatelephoneconversationisnodifferentthanadatapacketcontainingpartofanemail.Fromtheperspectiveoftheendpoints,differenttypesoftraffichavedisparatedeliveryrequirements.
Forexample,emailtrafficistypicallyhandledusingthestore-and-forwardprocess.Itdoesnothavetohappeninrealtime.Anemailtransmissiondoesnothavetobestreamedfromoneendpointtoanotherendpointtobesuccessful.Conversely,VoIPtrafficdemandsreal-timededicatedbandwidthforanallottedtime.TocompleteasuccessfulVoIPsession,thenetworkmustbeabletoclassifyandmarkvoicetrafficashighpriority,guaranteebandwidthandsupportuninterruptedstreamingVoIPpacketsbetweentwoendpointsforthedurationofthephoneconversation.
TosupportVoIPtrafficconsistentlyandreliably,anetworkmustbeabletoprovidefourthings:highperformance,lowlatencyandlowjitter,protectionandQoS.Thesefourthingshelpensurethatvoicepacketsaresentthroughthenetworkinrealtime.
Preserving VoIP Traffic with Advanced Traffic Management and Bandwidth Prioritization Tools IdealforsupportingVoIPtrafficbyminimizinglatencyandjitter,ExtremeNetworksswitchesofferPolicy-basedQoS–anadvancedtrafficmanagementtoolwhichprovidesbidirectionalminimumandmaximum
Packets In Packets Out
1 6 4
1 6 43 5 2
6 1 Increasing Priority Packets QpX - Essential Traffic
Qp1 - Best Effort Traffic
Higher Priority
Lower Priority
Classification
6 5 4
3 2 1
Figure 2: Policy-Based QoS in Action
Maximizing VoIP Performance AnExtremeNetworksapplicationsinfrastructureleveragespowerfulswitchingandQoScapabilitiesthatareinherentinBlackDiamond®andSummit®switches:
• Wire-speedswitchingandroutingperformance–Wire-speedswitchingatLayer2andLayer3ensuresthatthepacketforwardingspeed,whetheritisforadatapacketcontainingpartofanemailoraVoIPpacketcontainingpartofatelephoneconversation,willminimizeobstaclestodeployingVoIPontheLAN.
Extreme Networks Voice-over-IP (VoIP) Solution Overview
© 2009 Extreme Networks, Inc. All rights reserved. Extreme Networks Voice-over-IP (VoIP) Solution Overview—Page 3
Figure 2: Medium Enterprise Data Center
• Non-blockingarchitecture–EveryExtremeNetworksswitchhasanon-blockingswitchfabric,whichenableswire-speedswitchingandroutingperformancewithoutbeingasourceofcongestionorpacketlossforVoIPtraffic.
• Lowlatency–Aby-productofwire-speedswitchingislowtrafficforwardinglatency.ExtremeNetworksswitchesonlyintroduce8-12microseconds(msec)oflatency,ordelay,whenforwardinga64-byteEthernetpacketatLayer2orLayer3.Thisislessthanthe150-300milliseconds(ms)ofdelaythatVoIPpacketscantolerate.Consequently,thepacket-forwardingdelayincurredbyExtremeNetworkswitchesisover1,000timeslessthanthemaximumdelayVoIPtrafficwilltolerate.
• Lowjitter–Jitterisameasureofthevariationinlatencyovertime.Inanidealsituationwithnojitter,everypacketarrivesatitsdestinationwiththeexactsameamountoflatencyoveraninfiniteperiodoftime.Therealitywithallnetworksisthatsomeamountofjitterwillexist.Thechallengeistominimizethatjitter.ExtremeNetworksswitchesexhibitanaveragejitterof10microseconds(msec).Jitteroflessthan1millisecond(ms)isoptimalforVoIPtraffic.Therefore,theExtremeNetworksjitterrateisathousandtimescloserto0thanwhatisrequiredforasuccessfulVoIPsession.
Maximizing VoIP Resiliency PerformanceisjustonecriticalcomponentofasuccessfulVoIPimplementation.Anothermajorcomponenttoconsiderisbuildingahighlyresilientinfrastructureformaximumuptimeandsustainingfailureswhilekeepingthevoiceenvironmentinproduction.
ExtremeNetworksproductsprovideagilenetworkinfrastructuresolutionstokeepaheadofthegrowingbandwidthandresiliencydemandsintoday’salways-onenvironments.ThroughoutallExtremeNetworksdesignsthesethreekeyfeaturesprovideahighlyresilientinfrastructure:
• ExtremeXOS-aconsistentoperatingsystemacrossallswitchingplatforms
• EthernetAutomaticProtectionSwitching(EAPS)protocolforcarrierclassLayer2resiliency
• ExtensibilitywithWidgetscriptingandtightintegrationofexternalapplicationsviaExtremeXOSInSite(XMLSDK)
ExtremeXOSExtremeNetworksmodularedgetocoreoperatingsystem,ExtremeXOS,raisesthebarforavailabilityto
supportmission-criticalvoiceapplications.Ahighlyavailablenetworkcanalsoloweroperationalcostsbydrasticallyreducingemergencymaintenance.
TheExtremeXOSoperatingsystemhasarichsetofLayer2andLayer3controlprotocols,providesflexibilityinthedesignofhighlyresilientnetworksandhasbeendesignedfromthegrounduptosupportthenext-generationInternetProtocol,IPv6.EvenwhennotplanningtouseIPv6,ExtremeXOScanhelpsecurethenetworkusingIPv6AccessControlLists(ACLs)andhelpprovideinvestmentprotectionforthenetwork.SecuritycapabilitiesprovidenetworkcontrolandmanagementplaneprotectionviaCLEAR-FlowwhenpairedwithSentriant®NG300,ExtremeNetworksbehavior-basedthreatdetectionsolution.ExtremeXOSdramaticallyincreasesnetworkavailabilityusingprocessmonitoringandrestart.EachindependentOSprocessismonitoredinrealtime.Ifaprocessbecomesunresponsiveorstopsrunning,itmaybepossibletoautomaticallyrestart,ortakeotherautomaticcorrectiveactions,suchashitlessfailovertoaredundantmanagementmoduleorstandbystackmaster.
Ethernet Automatic Protection Switching (EAPS)Theconvergednetworkinfrastructureisrequiredtoofferscalableandagileresponsestotheever-growingdemandsofincreasingreal-timeapplications.Theunderlyingswitchinginfrastructuremusthavetheintelligenceandagilitytoaddressresiliencyissues,butdosowithsimpleandefficientsolutions.
ExtremeNetworksmeetsthisrequirementwithitsinnovativeEthernetAutomaticProtectionSwitching(EAPS)solution.Leveragingadesignfromcarrier-classresiliencysolutions,EAPSresilientring-basedtopologyisextensivelydeployedinenterprisenetworksandiswellsuitedtomeetthedemandsofconvergednetworks.
EAPSwasdesignedtoovercomethebroadcastloopproblemofEthernetnetworksandtoprovidefastrecoveryfromnetworklinkfailures.TheInternetEngineeringTaskForce(IETF)laterstandardizedtheEAPSprotocolinRFC3619.Instandardnetworkarchitectures,linkfailuresrecoverinfewerthan50millisecondswhichisequivalenttotheperformanceofSONETandSDHrecoverysolutions.ThistypeofresiliencyiscriticalfordatacentersandmissioncriticalVoIPapplications.EAPSenablesoperationalagilitybysimplifyingnetworkrecoveryinaconverged,virtualizedscalablenetwork.
Extreme Networks Voice-over-IP (VoIP) Solution Overview
© 2009 Extreme Networks, Inc. All rights reserved. Extreme Networks, the Extreme Networks Logo, BlackDiamond, EPICenter, ExtremeXOS, Sentriant and Summit are either registered trademarks or trademarks of Extreme Networks, Inc. in the United States and/or other countries. Specifications are subject to change without notice. 1294_02 5/09
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Benefits of EAPS
• Sub-50msRecoveryTimeforLinkorNodeFailures:Whenalinkfailureorswitchfailureoccursincommonnetworkarchitectures,EAPSrecoverswithin50milliseconds,arecoverytimecomparabletoSONETandSDH.
• ScalableNetworkSegmentationandFaultIsolation:EAPSDomainscanprotectgroupsofmultipleVLANsallowingscalablegrowthandbroadcastloopprotection.EAPSDomainsprovidelogicalandphysicalsegmentation,whichmeansfailuresinoneEAPSringwillnotimpactotherEAPSringsandVLANs.
• ResilientFoundationforNon-StopIPRoutingServices:EAPSprovidesaresilientfoundationforupper-levelroutingprotocolssuchasOpenShortestPathFirst(OSPF)andBorderGatewayProtocol(BGP),minimizingroute-flappinganddroppedneighborswithintheroutedIPnetwork.
• PredictableRecoveryTimesRegardlessofFailureLocation:EAPSprovidesconsistentandpredictablerecoverybehaviorregardlessofwherelinkfailuresoccur.Thesimpleblockingarchitec-tureandpredictableperformanceofEAPSallowforenforceableServiceLevelAgreements(SLAs).Thisaffordseasiernetworktroubleshootingandfailurescenarioanalysiswithoutlengthytestingordebuggingondatacenternetworks.
ExtensibilityExtremeNetworksoffersanExtensibleEcosystemconsistingofDevice,Network,andHumanExtensibility.DeviceExtensibility:SwitchControlthroughExtremeXOS
Networkadministratorscansimplifymanagementprocesseswithautomationwidgets.WidgetsarescriptswhichhelpsimplifyandautomateITtasks.Theyconsistoftwosimilartechnologies;CLIScripting(StaticScripts)andUniversalPort(DynamicScripting.)CLIorStaticScriptingallowsyoutoautomateandreplicateanysetofcommandsthatareavailabletotheadministratorfromthecommandlineinterface.Thisfeatureenablesconsistentconfigurationmanagementordeploymentofnewequipmentwithoutthedangerofconfigurationerrors.Additionallogiccontrolandanalysisismade
availablethroughtheuseoftheTclscriptingfacilities.UniversalPort(DynamicScripting)advancestheconceptofstaticscriptingthroughtriggerbasedbehaviorwhichenablesthenetworkstoactonbehalfofyourITstaffwhenseveraltypesofeventsarerecognized.Advancedcontrolandanalysisforbuildingnetwork-awareapplicationsareprovidedwithExtremeXOSInSiteXMLSoftwareDevelopmentKit(SDK)at:http://www.extremenetworks.com/solutions/Insite.aspx.ThisXMLinfrastructureembracestheconceptofopenyetsecurecommunicationstoallowbusinessapplica-tionstoeasilyinteractwiththenetworkforsecuritypolicyenforcement,regulatorycomplianceandperfor-mancemanagement,andhighersecurity.Theconfigu-rationandmonitoringcapabilitiesprovidedbytheAPIsletyoucreateServiceOrientedArchitecturesolutionsthatbridgethegapbetweenapplicationandbusinesslogicwithnetworkconfigurationandevents.TheXMLSDKcanenableapplicationstocontroltheinfrastructurewithapplicationssuchas:integrationwithSalesForce.comtoautomateaserviceprovisioningtemplatefordatabaseaccesstoanewcustomerorallowingaserverloadbalancertodetermineasetofservers(allhousedonacommonswitch)arenotneededandputtingtheswitchinlowpowermode.NetworkExtensibility:NetworkControlthroughEPICenter®andSecurityAppliances
ExtremeNetworksEPICenternetworkmanagementapplicationcanapplyTclscriptsforautomationofnetworkeventswhichcancontrolmanyswitches.Networkadministratorshavetheabilitytoaddtheirowncustomfeatures,whethertheyareverysimpleorextremelycomplex,throughscripts.TheonlyknowledgeneededisthesequenceofCLIcommandsneededtodoatask.Administratorscanrapidlycreateanddeploycustomfeaturesandtasksasneeded.HumanExtensibility:WidgetsDistributionthroughWidgetCentral
WidgetCentralisExtremeNetworksportalfordistributionofthewidgetsanddisseminationofextensibilityknowledge.YoucanaccessWidgetCentralat:http://www.extremenetworks.com/solutions/widget-central.