ab330 (external session) you can’t fix it if you can’t see ... · •protocol analysis...

@ArubaNetworks | #ATM18

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YouCan’tFixItIfYouCan’tSeeItWirelessProtocolandSpectrumAnalysis

RobertBartz


@eightotwo

Presenter- RobertBartz

• Eight-O-TwoTechnologySolutions,DenverColorado• Engineer,Consultant,Educator,TechnicalAuthor,CWNE• BSDegree,IndustrialTechnology,CaliforniaStateUniversityLongBeach,College

ofEngineering• FormerAerospaceTestEngineer• 25YearsTechnicalTrainingWiththeLast17YearsSpecializinginWireless

Networking• Author- CWTSOfficialStudyGuidebySybex– 1st and2nd Editions• Author- MobileComputingDeploymentandManagement:RealWorldSkillsfor

CompTIAMobility+CertificationandBeyondbySybex• Author- CWTS,CWS,andCWTCompleteStudyGuidebySybex• E-mail:[email protected] Twitter: @eightotwo


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Agenda• CommonTroubleshootingMethodology• TheOSIModel(AQuickReview)• OSIModel– TheWirelessElement• TheIEEE802.11Frame• CommonIEEE802.11FrameExchanges• WirelessLANTroubleshootingToolsforLayer2(DataLink)• ProtocolAnalysis• WirelessLANTroubleshootingToolsforLayer1(Physical)• SpectrumAnalysis


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Thisisanolollygaggingsessionlol·ly·gagˈlälēˌɡaɡ/verbNorthAmericaninformalgerundorpresentparticiple:lollygaggingspendtimeaimlessly;idle."hesendshertoArizonaeveryJanuarytolollygaginthesun"


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CommonTroubleshootingMethodologyStepsinacommontroubleshootingmethodology

1. Identifytheproblem2. Determinethescaleoftheproblem3. Possiblecauses4. Isolatetheproblem5. Resolutionorescalation6. Correctiveaction/verifysolution7. Document,documentand

document


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YouCan'tFixItIfYouCan'tSeeIt

TheOSIModel


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• Thebasicconceptofcommunicationsinthecomputernetworkenvironment

• Consistsofsevenlayers• Eachlayerismadeupofmanyprotocols

andservesaspecificfunction• Dataisencapsulatedatsomelayers• WLANtechnologyoperatesatthetwo

lowestlayers

TheOSIModel(AQuickReview)OpenSystemsInterconnection(OSI)


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Layer2– DataLinkLayer(MAC)TwosublayersResponsiblefororganizingthebit-leveldataforcommunications(frames)DetectingandcorrectingPhysicallayererrors

Layer1– PhysicalLayer(PHY)TwoSublayersBit-leveldatastreamsandcomputernetworkhardwareconnectingthedevicestogether

OSIModel– TheWirelessElementMSDU

MPDU

PPDU

The Media Access Control Service Data Unit (MSDU) is upper layer data that is encapsulated at the MAC and PLCP sublayers


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TheIEEE802.11Frame


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“SHOWMETHEMONEY”

TomCruiseasJerryMaguireinJerryMaguire(1996)

FamousQuotation#1


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“SHOWMETHEDATA”RobertBartzashimselfArubaAtmosphere#atm18LasVegas,Nevada(2018)

FamousQuotation#2


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TheIEEE802.11Frame

PacketsandFrames• Packetsareatlayer3

• Packetsencapsulatedata

• FramesareatLayer2• Framesencapsulatepackets

Packet

Frame


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TheIEEE802.11Frame

IEEE802.11- GeneralFrameFormat

ImageprovidedbyIEEEStd802.11™-2016


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TheIEEE802.11FrameFrameControlField


EveryIEEE802.11FrameHasaFrameControlField


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TheIEEE802.11Frame

TheThreeIEEE802.11FrameTypes• ManagementFrames• ControlFrames• DataFrames


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TheIEEE802.11FrameManagementFrameTypesinIEEE802.11Networking• CommonManagementFrames

• Beacon• PassiveScanning

• ProbeRequest/Response• ActiveScanning

• IEEE802.11Authentication• OpenSystem

• IEEE802.11AssociationRequest/Response• Capabilities


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TheIEEE802.11FrameControlFrameTypesinIEEE802.11Networking• CommonControlFrames

• RTS– RequesttoSend• Reservesthemedium

• CTS– CleartoSend• ResponsetoanRTS

• IEEE802.11ACK• Acknowledgesunicastframes

• PSPoll• Legacypowersavemode



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TheIEEE802.11Frame

DataFrameTypesinIEEE802.11Networking• TwoTypesofDataFrames

• Data• NullData



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TheIEEE802.11Frame

DataFramesTypesinIEEE802.11Networking• Data

• Carrydatapayload


Data (MSDU) is in the frame body


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TheIEEE802.11FrameDataFramesTypesinIEEE802.11Networking• NullData

• Doesnotcarrydatapayload• Powermanagement• Channelscanning• Maintaininganassociation

Power Management Bit


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CommonIEEE802.11FrameExchanges


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IEEE802.11FrameTypes

CommonIEEE802.11FrameExchanges• IEEE802.11AuthenticationandAssociation• IEEE802.11Pre-SharedKeyAuthentication• IEEE802.1X/EAPAuthentication


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IEEE802.11 AuthenticationandAssociation


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IEEE802.11Pre-SharedKeyAuthentication


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IEEE802.1X/EAPAuthentication


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WirelessLANTroubleshootingTools

CommonLayer2DataLinkaka(MACLayer)TroubleshootingTools


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Layer2DatalinkLayer(MAC)- TroubleshootingTools

Protocol(Packet)Analyzers• Wireshark• SavviusOmnipeek• NetscoutWi-FiAnalyzer• TamosoftCommViewforWi-Fi• MetaGeekEyeP.A.


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ThroughputTestTools• Tamosoft- Free• jPerf- Free• iPerf- Free


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Throughputtesttoolsarenotjustforthroughputtesting• Getdatamovingforvarioustestingpurposes


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AdditionalSoftwareTroubleshootingTools

Wi-FiDiscoveryTools• AcrylicWiFiHome(Windows)- Free• AirGrabWiFiRadar(MacOSX)- Free• LizardSystemsWi-FiScanner(Windows)

Freeandpurchaseversion


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AdditionalSoftwareTroubleshootingTools

Wi-FiDiscoveryTools• MetaGeekInSSIDerOffice- Purchase• NetSpot(WindowsandMac)• WiFiExplorer(Mac)– Freeandpurchase

version• Xirrus(Riverbed)W-FiInspector(Windows

andMac)- Free


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HardwareTroubleshootingTools

Wi-FiTestTools• NetscoutLinkSprinter• NetscoutAirCheckG2• BerkeleyVaritronicsYellowjacket-BANG• NetscoutOptiViewXG


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ProtocolAnalysis


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Troubleshooting Tools– ProtocolAnalyzers

TypesofProtocolAnalyzers• Portable(Laptop)• Infrastructure(AccessPoints)• Distributed(Sensors)


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TroubleshootingTools– ProtocolAnalyzers

NetworkAdapterandOperationModes• MonitorvsPromiscuousMode• SupportedAdapters• AdapterCapabilities


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Troubleshooting Tools– ProtocolAnalyzers

ProtocolAnalyzersPlacement• NearAccessPoint?• NearUser?• Moving?


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CommonProtocolAnalyzersSettings• Filters• RFChannel/Transitioning• SavetoDisk• Naming


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ProtocolAnalyzersPacketList• MACAddressInformation• ProtocolTypes• Timing


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ProtocolAnalyzersDecodes• RadiotapHeader/PacketInfo• NotLayer2Information• DerivedfromPhysicalLayerHeaderorDriver


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ProtocolAnalyzersGeneralInformation• ChannelInformation• Statistics


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So,Let’sGetPhysical


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WirelessLANTroubleshootingTools

CommonLayer1PhysicalLayer(akaThePHY)TroubleshootingTools


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Layer1PhysicalLayer(PHY)- TroubleshootingTools

InstrumentationSpectrumAnalyzers• Tektronix• Rohde&Schwarz• RFExplorer


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Wi-FiCentricSpectrumAnalyzers• MetaGeekChanalyzer+Wi-SpyDBx• NetscoutSpectrumXT• EkahauSidekick• Notjustfortroubleshooting

– Spectrumanalyzersarealsousedwithdesign


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SiteSurvey/DesignSoftware• NetscoutSurveyPro• EkahauSiteSurvey• TamosoftTamoGraph


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SpectrumAnalysis


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TroubleshootingTools– SpectrumAnalyzers

SpectrumAnalysisAllowsYouTo• “See”YourWi-Fi

– VisualizeUnboundedMedium

• ViewInterferenceTypes– BothWi-FiandNon-Wi-Fi


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ViewKeyInformation• SignalStrength

– Receivedsignal(-55dBm)

• RFNoiseFloor– Unwantedsignal(-95dBm)

• SignaltoNoiseRatio(SNR)– Differencebetweensignalandnoise

» -55dBm– (-95dBm)=+40dBm


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ViewKeyInformation• RealTimeFFT

– Amplitudeoverfrequency

• Waterfall– RFsignaloveraperiodoftime

• ChannelUtilization– RFactivityonthechannel


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SpectrumAnalysisAllowsYouToSee• Co-channelInterference(Wi-Fi)• OverlappingChannelInterference(Wi-Fi)• Non-Wi-FiInterference• MuchMore


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SpectrumAnalyzerDemonstration


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Questions?

Whatisthebestwaytolearnprotocolanalysis?Justdoit!

Howmuchdothetoolscost?Varyfromfreetomanythousandsofdollars


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ThankYou!RobertBartzE-mail: [email protected]: @eightotwo

ab330 (external session) you can’t fix it if you can’t see ... · •protocol analysis...

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