Specifications

December 02, 2010 Page 1 of 5
Flex-Edge
ThisdocumentdescribestheFlex‐EdgecapabilityontheEnterasysS‐Series
®
platform.
What is Flex-Edge
Flex‐Edgeisthecapabilitytoclassifyandprioritizetrafficasitenterstheswitch,assertflow
control,andensurethathigherprioritytrafficreceivedby theswitchisforwardedtothepacket
processoraheadoflowerprioritytraffic.WiththeseFlex‐Edgecapabilities,theswitchis
significantlylessvulnerableto
networkcongestionissuesatpeaktraffictimes.Trafficcriticalto
ensuringthe“alwaysup”operationalstateofthenetworkandtomaintainingapplication
continuityisidentifiedandprioritizedatingress,priortobeingpassedtothepacketprocessor.
Networkhighavailabilityisassured,andimportantusersandapplicationsareguaranteed
bandwidthandpriority.
ThediversityofIP‐enableddevices,combinedwithrealtimeapplicationssuchasVoIP,videoand
audiostreaming,andsoftware‐on‐demand,haveexponentiallyincreasednetworktrafficvolume.
Theintroductionofthesefunctionalitiescreatesaneedforbandwidthmanagementtoprevent
portoversubscriptionandassurethatthelowest
prioritypacketsaredroppedshouldport
oversubscriptionoccur.Flex‐Edgeprovideskeycomponentsofthatbandwidthmanagement
requirement.
PacketclassificationandprioritizationishandledbytheadvancedMediaAccessControl(MAC)
chip.Shouldcongestionstarttooccur,theMACchipiscapableofsendingaMACpauseoutthe
congestingport
requestingthatdownstreamportstemporarilystopsendingtraffictothedevice.
Flex‐Edgeforwardshigherprioritypacketstothepacketprocessoraheadoflowerpriority
packets.AnydroppingofpacketsishandledinthepacketbufferbyQoS.
Implementing Flex-Edge
Drop‐precedenceistheonlyadministrativelyconfigurableFlex‐Edgeparameter.Allother
Flex‐Edgeprocessingishardcoded.Drop‐precedenceisaCoSsettingthatisappliedtoapolicy
rule.Drop‐precedencecansetthepacketprioritytofavored,best‐effort,orunfavored.
For information about... Refer to page...
What is Flex-Edge 1
Implementing Flex-Edge 1
Flex-Edge Overview 2
Terms and Definitions 3