Switch User Manual

SecureStack C3 Configuration Guide 28-1

sFlow Configuration

ThischapterprovidesinformationaboutthecommandsusedtoconfigureandmonitorthesFlow

system.

Overview

sFlowisamethodformonitoringhigh‐speedswitchedandroutednetworks.sFlowtechnologyis

builtintonetworkequipmentandgivesvisibilityintonetworkactivity,enablingeffective

managementandcontrolofnetworkresources.

AnsFlowsolutionconsistsofansFlowAgent,embeddedinthenetworkdevicesuchasaswitch

or

router,andansFlowCollector.ThesFlowAgentusessamplingtechnologytocapturetraffic

statisticsfromthedeviceitismonitoringandimmediatelyforwardsthesampledtrafficstatistics

toansFlowCollectorforanalysisinsFlowdatagrams.

ThesFlowAgentusestwoformsofsampling—statisticalpacket‐basedsamplingofswitched

or

routedPacketFlows,andtime‐basedsamplingofcounters.

Version5 ofsFlowisdescribedindetailinthedocumententitled “sFlowVersion5”availablefrom

sFlow.org(http://www.sflow.org).

Using sFlow in Your Network

TheadvantagesofusingsFlowinclude:

•sFlowmakesitpossibletomonitorportsofaswitch,withnoimpactonthedistributed

switchingperformance.(See“UsageNotes”onpage 28‐3formoreinformation.)

•sFlowrequiresverylittlememoryorCPUusage.Samplesarenotaggregatedintoaflow‐

tableonthe

switch—theyareforwardedimmediatelyoverthe networktothesFlow

Collector.

•Thesystemistoleranttopacketlossinthenetwork.(Thestatisticalmodelmeanslossis

equivalenttoaslightchangeinthesamplingrate.)

•ThesFlowCollectorcanreceivedatafrommultipleswitches,providingareal‐time

synchronizedviewofthewholenetwork.

•ThesFlowCollectorcananalyzetrafficpatterns forwhateverprotocolsarefoundinthe

packetheaders(forexample,TCP/IP,IPX,Ethernet,AppleTalk).Thereisnoneedforthelayer

2switchtodecodeandunderstandallprotocols.

For information about... Refer to page...

Overview 28-1

Commands 28-4