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
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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.
