校园无线网络技术及应用发展英文版

27.12.20221校園無線網路技術與應用發展Sheng-TzongCheng

鄭憲宗stcheng@.tw..tw27.12.20222Outline無線區域網路─IEEE802.11無線應用通訊協定─WAP27.12.20223無線區域網路通訊協定WirelessLocalAreaNetwork(IEEE802.11)27.12.20224無線區域網路標準-IEEE802.11SpecifiesasingleMediumAccessControl(MAC)sublayerand3PhysicalLayerSpecifications.Stationscanoperateintwoconfigurations:Ad-hocmodeInfrastructuremodeThreePHYspecificationsFrequencyHoppingSpreadSpectrum(FHSS).DirectSequenceSpreadSpectrum(DSSS).InfraredPHY.27.12.20225IEEE802.11規範IEEEProject802Charter:Local&MetropolitanAreaNetwork1Mbpsto100Mbpsandhigher2lowerlayersof7LayerOSIReferenceModelIEEE802.11WorkingGroupscope:Wirelessconnectivityforfixed,portableandmovingstationswithinalimitedareaAppeartohigherlayer(LLC)thesameasexisting802standardsApplicationLayerNetworkLayerMACPhysicalLayer...LLCIEEE802.11DataLinkLayer27.12.202261997/6/26通過成為IEEE802系列標準IEEE802.11架構MediaAccessControlLogicalLinkControlInfraredPhysicalLayerFHSSPhysicalLayerDSSSPhysicalLayer27.12.20227AdHoc網路OneBasicServiceSetDirectedConnectionLimitedCoverageArea27.12.20228APBSSInfrastructure網路APBasicServiceSetExistingWiredLANDistributionSystemOtherLANsExtendServiceSet27.12.20229Infrastructure網路(cont.)AccessPointandMobileStationDistributedSystemInterconnectMultipleCellsviaAccessPointstoformasinglenetworkExtendsWirelessCoverageAreaMultipleBasicServiceSetsconnectedtogetherformanExtendedServiceSetAllowMobileStationtoaccessfixedresourceSupportRoamingforMobileStationsviaAccessPointPointCoordinationFunction,PowerManagement,TimeSynchronizationsupportthroughAccessPoint27.12.202210IEEE802.11ServicesProvidesserviceswiththefollowingfunctionality:roamingwithinaESS,multipledataratesinBSSsandPowerManagement.TheMACprotocolisCarrierSenseMultipleAccesswithCollisionAvoidance(CSMA/CA)MACservicesAssociationserviceAuthenticationserviceDistributionserviceIntegrationserviceDeauthentication/Deassociationservice25.12.202211SpreadSpectrumTechnologyDSSS（DirectSequenceSpreadSpectrum）11channelsPN-code長度為11-bit展頻寬度度為11MHzFHSS（FrequencyHoppingSpreadSpectrum）78hopsequences頻帶範圍圍為1MHz，跳頻的頻頻率為每每秒2.5次InfraredRay發展趨勢勢：DHSS往高速無無線區域域網路系系統發展展，適合合辦公室室環境使使用；FHSS會往低價價網路應應用發展展，提供供SOHO及家庭應應用、或或周邊設設備之無無線網路路連結。。25.12.202212直接序列列展頻（（DSSS）25.12.202213跳頻展頻頻（FHSS）25.12.202214IEEE802.11TGaTheTGaisworkingonthehighdata-rateextensioninthe5GHzband,project802.11a,wasabletoproduceanewdraftstandardthathasthesupportofatleast80%ofthemembers.TGaislookingatacandidateforworldwidestandardization!25.12.202215IEEE802.11TGa(cont.)ThespecificationsofthePhysicalLayerencompassdataratesfrom6Mbit/supto54Mbit/s,with20MHzspacingbetweenadjacentchannels.Allimplementationsarerequiredtosupport6,12and24Mbit/s.Optionalextensionsarefor9,18,36,48and54Mbit/s.Themulti-ratemechanismoftheMACprotocolensuresthatalldevicescommunicatewitheachotheratthebestdatarateinthepresentchannel.25.12.202216IEEE802.11TGbTheTGbisworkingontheextensionofthe1and2Mbit/sdataratesinthe2.45GHzbandwith5.5and11Mbit/shasreachedatechnicalcompromisesolutiontoimprovetheco-existenceandinteroperabilitycharacteristicsbetweenoptions.Themulti-ratemechanismwarrantsthatthe11Mbit/soperationcanswitchbackto5.5Mbit/s.Stationsthatareevenfurthercouldswitchbacktothe2and1Mbit/scapabilitiesoftheDSSSmodulation.25.12.202217CSMA/CD(LAN)Senddataifthemediumissensed“idle”Ifcollideswithotherhost(s),thenbackoffforarandomnumberoftimesRe-senddatalater25.12.202218HiddenTerminalProblemBACdatadata25.12.202219SolutiontoHTPBACRequestGrant25.12.202220DetectionofCollisionBACRequestRequest25.12.202221BACRequestAisGrantAisGrantDCollisionAvoidance25.12.202222RTS/CTS/data/ACKandNAVsetting25.12.202223SomeIFSrelationshipsandbasicaccessmethod25.12.202224RandombackofftimeBackofftime=INT(CW*Random())*aSlotTimeINT(x):小於或等於於x的最大整數數CW(contentionwindowparameter):介於CWmin和Cwmax間的整數,CW依序遞增的的順序為(7,15,31,63,127,255,255,255………)Random():介於0到1間的實數aSlotTime:傳送器開啟啟延遲+媒介傳遞延延遲+媒介忙碌偵偵測反應時時間25.12.202225AnexampleofexponentialincreaseofCW25.12.202226Backoffprocedure25.12.202227Transmissionofamulti-fragmentMPDUusingSIFS25.12.202228RTS/CTSwithfragmentedMSDU25.12.202229RTS/CTSwithtransmitterpriorityandmissedacknowledgment25.12.202230Directdata/ACKMPDU25.12.202231無線區域網網路軟體技技術架構WLANPlatformEmbeddedControlSoftwareWLANManagementUtilityNetworkApplicationsDSSSFHSSMediaAccessControlNetworkDriver(NDIS)SocketInterfaceMobileIPSNMPAgentSecurityDistributedServiceE-MailFileTransferRemoteAccessMobileDataDECTU-NIIorISMbandETSI25.12.202232無線應用通通訊協定WirelessApplicationProtocol(WAP)25.12.202233無線上網趨趨勢日本NTT的DoCoMo於2/1999推出無線上上網服務，，一年內累累積3百萬用戶，，每週增加加10萬人WAPForum於1997年成立，，至1999年12月全世界界有200家無線通通訊事業成成為會員(95%市市場之相關關業者投入入)1999年年，WAP是手機使使用者最熱熱門話題之之一25.12.202234無線上網趨趨勢(續)1999年在台灣銷銷售180萬隻手機前前兩大廠──Motorola於2000上半年年WAP手手機佔40%，下下半年100%投入入；Nokia則則佔30%。國內新上市市的手機六六到七成內內建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)25.12.202235全球無線通訊訊用戶成長25.12.202236預估未來WAP手機的佔有率率25.12.20223725.12.20223825.12.202239手持型元件之之延革25.12.20224025.12.202241bringtheinternetcontentandadvancedservicesto後PC時代代之userscreateaglobalwirelessprotocoltoworkacrossdifferingwirelessnetworktechnologiesenableapplicationstoscaleacrossavarietyoftransportoptionsanddevicetypesWhat’sWAPfor?25.12.202242WhatisdefinedinWAP?Micro-BrowserScriptingtoenhanceMScapabilitiesWTA/WTAIfortelephonefunctionality(e.g.callchains)ContentFormatsbusinesscard(vCard)calendarevent(vCalendar)LayeredTelecommunicationStack25.12.202243Comparison25.12.20224425.12.202245GoalsforWTP(WAPv1.1)acommoninterfacetophysicaltransportmechanismsprovideaport-basedabstractinterfacetoupperlayerprotocolsallowapplicationsdesignedindependentfromspecifictransportsextensibletoavarietyofdigitalwirelessnetworksandfuturetransportoptions25.12.202246GoalsforWTP(cont.)supportsconnection-oriented,transaction,anddatagrammodesoptimizefornarrowtomediumbandwidthchannelstobecapableofimplementationinalowmemoryfootprint,suitableforstandardorlow-IQhandsets25.12.202247RequirementsforWTPWTP/Cprovidesareliableconnection-orientedservicetotheupperlayerWTP/Tprovidesareliabletransaction-orientedservicesuitableforwebbrowsingWTP/Dprovidesadatagramservicelightweight:implementablein<=10Kb(lowmemory/computationalneeds)25.12.202248WTP/Dfeatures(WDPinWAPv1.2)WTP/D(Datagram)providesaconnection-less,unreliabledatagramserviceWTP/DisreplacedbyUDPwhenusedoveranIPnetworklayer.usestheServicePrimitiveT-UnitData.req.ind25.12.202249WAPv1.2WirelessBearers: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)OtherServicesandApplications25.12.202250WTP/Tfeatures(WTPinWAPv1.2)WTP/T(Transaction)providesreliabledatatransferbasedonrequest/replyparadigmnoexplicitconnectionsetuporteardowndatacarriedinfirstpacketofprotocolexchangeseekstoreduce3-wayhandshakeoninitialrequest25.12.202251WTP/Tfeatures(cont.)supportsretransmissionoflostpacketsselective-retransmissionsegmentation/re-assemblyportnumberaddressing(specifictoWTP/T)flowcontrolmessageoriented(notstream)supportsanAbortfunctionforoutstandingrequests25.12.202252WirelessSessionProtocolWSP/BprovidesupperlayerswithsessionservicesandmanagementWSP/BProvidessemanticsandmechanismsbasedonHTTP1.1WSPprovidesmeansto:establishareliablesessionfromclienttoserveragreeoncommonlevelofprotocolfunctionalitybycapabilitynegotiationcompactencodingsuspendandresume25.12.202253WSPfeaturesHTTP1.1functionalityExchangeofclientandserversessionheadersInterruptmechanismfortransactionsinprocessContentPushfromservertoclientNegotiationformultiple,simultaneousasynchronoustransactions25.12.202254WTLSRecordProtocol4recordprotocolclients:ThehandshakeprotocolThechangecipherspecprotocolThealertprotocolTheapplicationdataprotocolWTLSconnectionstate:theoperatingenvironmentforrecordprotocolcompression/encryptionalgorithmMACalgorithm--keys25.12.202255RecordProtocolUsageHandshakeprotocolNegotiatesecureattributesofasecuresessionauthentication,securityparametersettingsChangecipherspecprotocolSignaltransitionsincipheringstrategiessentbeforeverifyingfinishedmessageAlertprotocolconveytheseverityofthemessageandadescriptionofthealert25.12.202256WirelessApplicationEnvironment(WAE)AnInternet(.)programmingmodelVendor-controlledMMIInitialfocusonphonesSlowbearersSmallmemoryLimitedCPUSmallscreenLimitedinputmodel25.12.202257WAEComponentsArchitecture–Applicationmodel–Browser,Gateway,ContentServerWML(WirelessMarkupLanguage)–DisplaylanguageWMLScript–ScriptinglanguageContentFormats–Dataexchange25.12.202258WAEIn-DeviceArchitecture25.12.202259WMLTag-basedbrowsinglanguage:Screenmanagement(text,images)Datainput(text,selectionlists,etc.)Hyperlinks&navigationsupportSyntax:W3CXML(SGMLderivative)InheritstechnologyfromHDMLandHTML25.12.202260WML(cont.)CardmetaphorUserinteractionsaresplitintocardsNavigationoccursbetweencardsStatemanagementandvariablesReducenetworktrafficResultsinbettercachingExplicitinter-cardnavigationmodelHyperlinksUIEventhandlingHistory25.12.202261WMLExample25.12.202262WMLScriptScriptinglanguage:Procedurallogic,loops,conditionals,etc.Optimizedforsmall-memory,small-cpudevicesDerivedfromJavaScript™IntegratedwithWMLPowerfulextensionmechanismReducesoverallnetworktraffic25.12.202263WMLScript(cont.)Bytecode-basedvirtualmachineStack-orienteddesignROM-ableDesignedforsimple,low-impactimplementationCompilerinnetworkBetternetworkbandwidthuseBetteruseofterminalmemory/cpu25.12.20226425.12.20226525.12.20226625.12.202267WAPGateway25.12.202268WAPApplicationServer25.12.20226925.12.202270WAPPushTechnologyPushAccessProtocolPushOver-the-AirProtocolPushProxy

GatewayPushInitiatorWAPClient25.12.202271WAP怎麼了？歐洲在兩年年內至少應應有10億隻WAP手機，實際際上只有六六百萬之使使用量(accordingtoIDC)T-Mobile:1%outof1300萬人採購上上網手機。。1%者有有1/3從從未上網，，大部份人人一週上網網不到一次次(北歐情情形較佳)影響WAP三大因素素(訊通國國際)：連連線速度慢慢、通信費費用高、服服務項目少少25.12.202272WAP整體環境手機製造業業電信系統業業者ISP設備供應商商網路軟體業業者提供個個人的、即即時的、必必須的資訊訊內容25.12.20227325.12.20227425.12.202275行動圖書館館操作模式式25.12.202276行動網路圖圖書館示意意圖25.12.202277行動網路圖圖書館架構構25.12.202278行動圖書館館運作流程程25.12.202279行動動圖圖書書館館服服務務功功能能25.12.202280行動動圖圖書書館館優優點點穩定定強強大大的的後後端端資資料料庫庫友善善使使用用者者的的DBA管理理介介面面跨平平台台執執行行之之服服務務程程式式充滿滿創創意意之之各各項項行行動動圖圖書書館館服服務務自行行架架設設之之WAPGatewayServer伺服服器器皆皆採採用用開開放放原原始始碼碼之之Linux作業業系系統統革命命性性跨跨介介面面存存取取的的多多元元圖圖書書館館25.12.202281行動動圖圖書書館館網網頁頁範範例例9、静夜四无邻邻，荒居旧业业贫。。12月-2212月-22Sunday,December25,202210、雨中黄叶树树，灯下白头头人。。00:54:3200:54:3200:5412/25/202212:54:32AM11、以我独沈久久，愧君相见见频。。12月-2200:54:3200:54Dec-2225-Dec-2212、故人江海别别，几度隔山山川。。00:54:3200:54:3200:54Sunday,December25,202213、乍见翻疑疑梦，相悲悲各问年。。。12月-2212月-2200:54:3200:54:32December25,202214、他乡生白白发，旧国国见青山。。。25十二二月202212:54:32上上午00:54:3212月-2215、比比不不了了得得就就不不比比，，得得不不到到的的就就不不要要。。。。。十二二月月2212:54上上午午12月月-2200:54December25,202216、行行动动出出成成果果，，工工作作出出财财富富。。。。2022/12/250:54:3200:54:3225December202217、做做前前，，能能够够环环视视四四周周；；做做时时，，你你只只能能或或者者最最好好沿沿着着以以脚脚为为起起点点的的射射线线向向前前。。。。12:54:32上上午午12:54上上午午00:54:3212月月-229、没没有有失失败败，，只只有有暂暂时时停停止止成成功功！！。。12月月-2212月月-22Sunday,December25,202210、很多多事情情努力力了未未必有有结果果，但但是不不努力力却什什么改改变也也没有有。。。00:54:3200:54:3200:5412/25/202212:54:32AM11、成功功就是是日复复一日日那一一点点点小小小努力力的积积累。。。12月月-2200:54:3200:54Dec-2225-Dec-2212、世间间成事事，不不求其其绝对对圆满满，留留一份份不足足，可可得无无限完完美。。。00:54:3200:54:3200:54Sunday