无线网路技术的应用

校園無線網路技術與應用發展Sheng-TzongCheng

鄭憲宗stcheng@.tw.tw06-2757575ext.625291/7/20231Outline無線區域網路─IEEE802.11無線應用通訊協定─WAP1/7/20232無線區域網路通訊協定WirelessLocalAreaNetwork(IEEE802.11)1/7/20233無線區域網路標準-IEEE802.11SpecifiesasingleMediumAccessControl(MAC)sublayerand3PhysicalLayerSpecifications.Stationscanoperateintwoconfigurations:Ad-hocmodeInfrastructuremodeThreePHYspecificationsFrequencyHoppingSpreadSpectrum(FHSS).DirectSequenceSpreadSpectrum(DSSS).InfraredPHY.1/7/20234IEEE802.11規範IEEEProject802Charter:Local&MetropolitanAreaNetwork1Mbpsto100Mbpsandhigher2lowerlayersof7LayerOSIReferenceModelIEEE802.11WorkingGroupscope:Wirelessconnectivityforfixed,portableandmovingstationswithinalimitedareaAppeartohigherlayer(LLC)thesameasexisting802standardsApplicationLayerNetworkLayerMACPhysicalLayer...LLCIEEE802.11DataLinkLayer1/7/202351997/6/26通過成為IEEE802系列標準IEEE802.11架構MediaAccessControlLogicalLinkControlInfraredPhysicalLayerFHSSPhysicalLayerDSSSPhysicalLayer1/7/20236AdHoc網路OneBasicServiceSetDirectedConnectionLimitedCoverageArea1/7/20237APBSSInfrastructure網路APBasicServiceSetExistingWiredLANDistributionSystemOtherLANsExtendServiceSet1/7/20238Infrastructure網路(cont.)AccessPointandMobileStationDistributedSystemInterconnectMultipleCellsviaAccessPointstoformasinglenetworkExtendsWirelessCoverageAreaMultipleBasicServiceSetsconnectedtogetherformanExtendedServiceSetAllowMobileStationtoaccessfixedresourceSupportRoamingforMobileStationsviaAccessPointPointCoordinationFunction,PowerManagement,TimeSynchronizationsupportthroughAccessPoint1/7/20239IEEE802.11ServicesProvidesserviceswiththefollowingfunctionality:roamingwithinaESS,multipledataratesinBSSsandPowerManagement.TheMACprotocolisCarrierSenseMultipleAccesswithCollisionAvoidance(CSMA/CA)MACservicesAssociationserviceAuthenticationserviceDistributionserviceIntegrationserviceDeauthentication/Deassociationservice12/29/202210SpreadSpectrumTechnologyDSSS（DirectSequenceSpreadSpectrum）11channelsPN-code長度為11-bit展頻寬度為11MHzFHSS（FrequencyHoppingSpreadSpectrum）78hopsequences頻帶範圍為1MHz，跳頻的頻率為為每秒2.5次InfraredRay發展趨勢：DHSS往高高速無線區域域網路系統發發展，適合辦辦公室環境使使用；FHSS會往低價價網路應用發發展，提供SOHO及家家庭應用、或或周邊設備之之無線網路連連結。12/29/202211直接序列展頻頻（DSSS）12/29/202212跳頻頻展展頻頻（（FHSS））12/29/202213IEEE802.11TGaTheTGaisworkingonthehighdata-rateextensioninthe5GHzband,project802.11a,wasabletoproduceanewdraftstandardthathasthesupportofatleast80%ofthemembers.TGaislookingatacandidateforworldwidestandardization!12/29/202214IEEE802.11TGa(cont.)ThespecificationsofthePhysicalLayerencompassdataratesfrom6Mbit/supto54Mbit/s,with20MHzspacingbetweenadjacentchannels.Allimplementationsarerequiredtosupport6,12and24Mbit/s.Optionalextensionsarefor9,18,36,48and54Mbit/s.Themulti-ratemechanismoftheMACprotocolensuresthatalldevicescommunicatewitheachotheratthebestdatarateinthepresentchannel.12/29/202215IEEE802.11TGbTheTGbisworkingontheextensionofthe1and2Mbit/sdataratesinthe2.45GHzbandwith5.5and11Mbit/shasreachedatechnicalcompromisesolutiontoimprovetheco-existenceandinteroperabilitycharacteristicsbetweenoptions.Themulti-ratemechanismwarrantsthatthe11Mbit/soperationcanswitchbackto5.5Mbit/s.Stationsthatareevenfurthercouldswitchbacktothe2and1Mbit/scapabilitiesoftheDSSSmodulation.12/29/202216CSMA/CD(LAN)Senddataifthemediumissensed““idle”Ifcollideswithotherhost(s),thenbackoffforarandomnumberoftimesRe-senddatalater12/29/202217HiddenTerminalProblemBACdatadata12/29/202218SolutiontoHTPBACRequestGrant12/29/202219DetectionofCollisionBACRequestRequest12/29/202220BACRequestAisGrantAisGrantDCollisionAvoidance12/29/202221RTS/CTS/data/ACKandNAVsetting12/29/202222SomeIFSrelationshipsandbasicaccessmethod12/29/202223RandombackofftimeBackofftime=INT(CW*Random())*aSlotTimeINT(x):小小於於或等等於x的最最大整整數CW(contentionwindowparameter):介介於於CWmin和和Cwmax間間的整整數,CW依序序遞增增的順順序為為(7,15,31,63,127,255,255,255………)Random():介介於於0到到1間間的實實數aSlotTime:傳傳送器器開啟啟延遲遲+媒媒介傳傳遞延延遲+媒媒介介忙碌碌偵測測反應應時間間12/29/202224AnexampleofexponentialincreaseofCW12/29/202225Backoffprocedure12/29/202226Transmissionofamulti-fragmentMPDUusingSIFS12/29/202227RTS/CTSwithfragmentedMSDU12/29/202228RTS/CTSwithtransmitterpriorityandmissedacknowledgment12/29/202229Directdata/ACKMPDU12/29/202230無線區域網網路軟體技技術架構WLANPlatformEmbeddedControlSoftwareWLANManagementUtilityNetworkApplicationsDSSSFHSSMediaAccessControlNetworkDriver(NDIS)SocketInterfaceMobileIPSNMPAgentSecurityDistributedServiceE-MailFileTransferRemoteAccessMobileDataDECTU-NIIorISMbandETSI12/29/202231無線線應應用用通通訊訊協協定定WirelessApplicationProtocol(WAP)12/29/202232無線線上上網網趨趨勢勢日本本NTT的的DoCoMo於2/1999推推出出無無線線上上網網服服務務，，一一年年內內累累積積3百百萬萬用用戶戶，，每每週週增增加加10萬萬人人WAPForum於1997年年成成立立，，至至1999年年12月月全全世世界界有有200家家無無線線通通訊訊事事業業成成為為會會員員(95%市市場場之之相相關關業業者者投投入入)1999年，，WAP是手手機使用者最最熱門話題之之一12/29/202233無線上網趨勢勢(續)1999年在在台灣銷售180萬隻手手機前兩大廠廠─Motorola於2000上半年WAP手機佔40%，下下半年100%投入；Nokia則則佔30%。國內新上市的的手機六到七七成內建WAP功能台灣已超過1000萬人人有行動手機機，而PC上上網人數約3至4百萬語音：數據──95%:5%(2000);40%:60%(2005)12/29/202234全球無無線通通訊用用戶成成長12/29/202235預估未未來WAP手機的的佔有有率12/29/20223612/29/20223712/29/202238手持型元件件之延革12/29/20223912/29/202240bringtheinternetcontentandadvancedservicesto後PC時時代代之之userscreateaglobalwirelessprotocoltoworkacrossdifferingwirelessnetworktechnologiesenableapplicationstoscaleacrossavarietyoftransportoptionsanddevicetypesWhat’’sWAPfor?12/29/202241WhatisdefinedinWAP?Micro-BrowserScriptingtoenhanceMScapabilitiesWTA/WTAIfortelephonefunctionality(e.g.callchains)ContentFormatsbusinesscard(vCard)calendarevent(vCalendar)LayeredTelecommunicationStack12/29/202242Comparison12/29/20224312/29/202244GoalsforWTP(WAPv1.1)acommoninterfacetophysicaltransportmechanismsprovideaport-basedabstractinterfacetoupperlayerprotocolsallowapplicationsdesignedindependentfromspecifictransportsextensibletoavarietyofdigitalwirelessnetworksandfuturetransportoptions12/29/202245GoalsforWTP(cont.)supportsconnection-oriented,transaction,anddatagrammodesoptimizefornarrowtomediumbandwidthchannelstobecapableofimplementationinalowmemoryfootprint,suitableforstandardorlow-IQhandsets12/29/202246RequirementsforWTPWTP/Cprovidesareliableconnection-orientedservicetotheupperlayerWTP/Tprovidesareliabletransaction-orientedservicesuitableforwebbrowsingWTP/Dprovidesadatagramservicelightweight:implementablein<=10Kb(lowmemory/computationalneeds)12/29/202247WTP/Dfeatures(WDPinWAPv1.2)WTP/D(Datagram)providesaconnection-less,unreliabledatagramserviceWTP/DisreplacedbyUDPwhenusedoveranIPnetworklayer.usestheServicePrimitiveT-UnitData.req.ind12/29/202248WAPv1.2WirelessBearers:SMSUSSDCSDIS-136CDMAIDENCDPDPDC-PGPRSWirelessApplicationEnvironment(WAE)WirelessSessionProtocol(WSP)WirelessTransactionProtocol(WTP)WirelessTransportLayerSecurity(WTLS)Datagrams(UDP/IP)Datagrams(WDP)OtherServicesandApplicationsWirelessBearers:SMSUSSDCSDIS-136CDMAIDENCDPDPDC-PGPRSWirelessApplicationEnvironment(WAE)WirelessSessionProtocol(WSP)WirelessTransactionProtocol(WTP)WirelessTransportLayerSecurity(WTLS)Datagrams(UDP/IP)Datagrams(WDP)OtherServicesandApplications12/29/202249WTP/Tfeatures(WTPinWAPv1.2)WTP/T(Transaction)providesreliabledatatransferbasedonrequest/replyparadigmnoexplicitconnectionsetuporteardowndatacarriedinfirstpacketofprotocolexchangeseekstoreduce3-wayhandshakeoninitialrequest12/29/202250WTP/Tfeatures(cont.)supportsretransmissionoflostpacketsselective-retransmissionsegmentation/re-assemblyportnumberaddressing(specifictoWTP/T)flowcontrolmessageoriented(notstream)supportsanAbortfunctionforoutstandingrequests12/29/202251WirelessSessionProtocolWSP/BprovidesupperlayerswithsessionservicesandmanagementWSP/BProvidessemanticsandmechanismsbasedonHTTP1.1WSPprovidesmeansto:establishareliablesessionfromclienttoserveragreeoncommonlevelofprotocolfunctionalitybycapabilitynegotiationcompactencodingsuspendandresume12/29/202252WSPfeaturesHTTP1.1functionalityExchangeofclientandserversessionheadersInterruptmechanismfortransactionsinprocessContentPushfromservertoclientNegotiationformultiple,simultaneousasynchronoustransactions12/29/202253WTLSRecordProtocol4recordprotocolclients:ThehandshakeprotocolThechangecipherspecprotocolThealertprotocolTheapplicationdataprotocolWTLSconnectionstate:theoperatingenvironmentforrecordprotocolcompression/encryptionalgorithmMACalgorithm--keys12/29/202254RecordProtocolUsageHandshakeprotocolNegotiatesecureattributesofasecuresessionauthentication,securityparametersettingsChangecipherspecprotocolSignaltransitionsincipheringstrategiessentbeforeverifyingfinishedmessageAlertprotocolconveytheseverityofthemessageandadescriptionofthealert12/29/202255WirelessApplicationEnvironment(WAE)12/29/202256WAEComponentsArchitecture–Applicationmodel–Browser,Gateway,ContentServerWML(WirelessMarkupLanguage)–DisplaylanguageWMLScript–ScriptinglanguageContentFormats–Dataexchange12/29/202257WAEIn-DeviceArchitecture12/29/202258WMLTag-basedbrowsinglanguage:Screenmanagement(text,images)Datainput(text,selectionlists,etc.)Hyperlinks&navigationsupportSyntax:W3CXML(SGMLderivative)InheritstechnologyfromHDMLandHTML12/29/202259WML(cont.)CardmetaphorUserinteractionsaresplitintocardsNavigationoccursbetweencardsStatemanagementandvariablesReducenetworktrafficResultsinbettercachingExplicitinter-cardnavigationmodelHyperlinksUIEventhandlingHistory12/29/202260WMLExample12/29/202261WMLScriptScriptinglanguage:Procedurallogic,loops,conditionals,etc.Optimizedforsmall-memory,small-cpudevicesDerivedfromJavaScript™™IntegratedwithWMLPowerfulextensionmechanismReducesoverallnetworktraffic12/29/202262WMLScript(cont.)Bytecode-basedvirtualmachineStack-orienteddesignROM-ableDesignedforsimple,low-impactimplementationCompilerinnetworkBetternetworkbandwidthuseBetteruseofterminalmemory/cpu12/29/20226312/29/20226412/29/20226512/29/202266WAPGateway12/29/202267WAPApplicationServer12/29/20226812/29/202269WAPPushTechnologyPushAccessProtocolPushOver-the-AirProtocolPushProxy

GatewayPushInitiatorWAPClient12/29/202270WAP怎麼了？？歐洲在兩兩年內至至少應有有10億億隻WAP手機機，實際際上只有有六百萬萬之使用用量(accordingtoIDC)T-Mobile:1%outof1300萬人採購購上網手手機。1%者有有1/3從未上上網，大大部份人人一週上上網不到到一次(北歐情情形較佳佳)影響WAP三大大因素(訊通國國際)：：連線速速度慢、、通信費費用高、、服務項項目少12/29/202271WAP整體環境境手機製造造業電信系統統業者ISP設備供應應商網路軟體體業者提供供個人的的、即時時的、必必須的資資訊內容容12/29/20227212/29/20227312/29/202274行動圖書館館操作模式式12/29/202275行動動網網路路圖圖書書館館示示意意圖圖12/29/202276行動動網網路路圖圖書書館館架架構構12/29/202277行動圖書書館運作作流程12/29/202278行動圖書書館服務務功能12/29/202279行動圖圖書館館優點點穩定強強大的的後端端資料料庫友善使使用者者的DBA管理理介面面跨平台台執行行之服服務程程式充滿創創意之之各項項行動動圖書書館服服務自行架架設之之WAPGatewayServer伺服器器皆採採用開開放原原始碼碼之Linux作業業系統統革命性性跨介介面存存取的的多元元圖書書館12/29/202280行動圖圖書館館網頁頁範例例12/29/202281TechnologySupport跨元件(介介面)資訊訊存取個人化資訊訊服務智慧型資料料傳輸高效能執行行平台高可靠度系系統支援生物特徵辨辨識12/29/2022829、静静夜夜四四无无邻邻，，荒荒居居旧旧业业贫贫。。。。12月月-2212月月-22Thursday,December29,202210、雨中黄叶叶树，灯下下白头人。。。14:05:0514:05:0514:0512/29/20222:05:05PM11、以以我我独独沈沈久久，，愧愧君君相相见见频频。。。。12月月-2214:05:0514:05Dec-2229-Dec-2212、故人江海别别，几度隔山山川。。14:05:0514:05:0514:05Thursday,December29,202213、乍见翻翻疑梦，，相悲各各问年。。。12月-2212月-2214:05:0514:05:05December29,202214、他乡乡生白白发，，旧国国见青青山。。。29十十二二月20222:05:05下下午14:05:0512月月-2215、比不了得得就不比，，得不到的的就不要。。。。十二月222:05下下午12月-2214:05December29,202216、行动出成成果，工作作出财富。。。2022/12/2914:05:0514:05:0529December202217、做前，，能够环环视四周周；做时时，你只只能或者者最好沿沿着以脚脚为起点点的射线线向前。。。2:05:05下午午2:05下午午14:05:0512月-229、没有有失败败，只只有暂暂时停停止成成功！！。12月月-2212月月-22Thursday,December29,202210、很多事事情努力力了未必必有结果果，但是是不努力力却什么么改变也也没有。。。14:05:0514:05:0514:0512/29/20222:05:05PM11、成功就是是日复一日日那一点点点小小努力力的积累。。。12月-2214:05:0614:05Dec-2229-Dec-2212、世间成成事，不不求其绝绝对圆满满，留一一份不足足，可得得无限完完美。。。14:05:0614:05:0614:05Thursday,December29,202213、不不知知香香积积寺寺，，数数里里入入云