藍(lán)牙是一種支持設(shè)備短距離通信的無線電技術(shù)

BluetoothBluetoothisashort-rangecommunicationsupportequipment,radiotechnology,researchinrecentyearshasbecomeahottopicandgetawiderangeofapplicationsBluetoothtechnologyuseshigh-speedfrequencyhoppingandtimedivisionmultipleaccessandotheradvancedtechnology,closetothemostinexpensivedigitalequipmentwereseveralnetworklinkup.Bluetoothisanopen,short-rangewirelesscommunicationstechnologystandards.Itcanbeusedinarelativelyshortdistance,avarietyofcabletoreplacethecurrentprogram,throughwallsandotherobstacles,throughaunifiedshort-rangewirelesslinkbetweenvariousdigitaldevicesinaflexible,secure,lowcost,minormeritsconsumptionofvoiceanddatacommunications.Bluetoothasanewshort-rangewirelesscommunicationtechnologyhasbeenwidelyusedinvariousfields,whichprovideslow-cost,lowpower,shortdistancewirelesscommunication,constituteafixedandmobiledevicesinthepersonalnetworkcommunicationenvironment,makingcloserangeallkindsofinformationdevicestoseamlesslyshareresources.Bluetoothdevicesshouldbeinteroperable,thatis,anyBluetoothdeviceshouldbeabletoachievebetweentheinterconnection,includinghardwareandsoftware.ProtocolandprotocolstackdesignThemainprincipleistrytouseavarietyofhigh-levelagreements,ensurethattheexistingagreementsandtheintegrationofBluetoothtechnologyandinteroperabilitybetweenvariousapplications;takefulladvantageofthehardwareandsoftwarecompatiblewithBluetoothspecificationsystemandBluetoothspecificationisopen,tofacilitatethedevelopmentofnewapplications.SIGspecificneedsaccordingtotheprotocolisdividedinto4layers:coreagreement,RFCOMMcablereplacementagreement,TCScallcontrolprotocol,andhigh-levelagreementsassociatedwiththeInternetSinceBluetoothisaradiocommunicationstandardasthemedia,third-partyinformationmaybeeasilyintercepted,sotheBluetoothtechnologymusttakecertainsecuritymechanisms,particularlyintheelectronictradingapplications.Inordertoprovidesecurityandtousethecredibilityoftheinformation,thesystemmustbeintheapplicationlayerandlinklayersecuritymeasures.Asmarketdemand,moreandmoreBluetoothsiliconwillsoonputintoproduction.Hotels,postoffices,golfcourses,airports,retailmalls,conventioncentersandcommercialareasareequippedwithBluetoothtechnology.BluetoothSiGnowhas2,400membercompaniesin2015willreach1.4billionBluetoothchips,applicationmachinealmost7millionunits.ThedreamofswimmingintheBluetoothtechnology,you'llfindBluetoothtechnologycapableofanything.LittleattentiontotheInternetforhigh-techmarket,youwillfindBluetoothtechnologyfromthebirthoftheday,hasbeenplacedonhighexpectations.Ibelievethatwithfurtherdevelopmentofscienceandtechnology,Bluetoothtechnologywillbemorewidelyused.藍(lán)牙藍(lán)牙是一種支持設(shè)備短距離通信的無線電技術(shù)，近年來已經(jīng)成為研究的熱點問題并獲得了廣泛的應(yīng)用藍(lán)牙技術(shù)使用高速跳頻和時分多址等先進(jìn)技術(shù)，在近距離內(nèi)最廉價地將幾臺數(shù)字化設(shè)備呈網(wǎng)狀鏈接起來。藍(lán)牙是一個開放性的、短距離無線通信技術(shù)標(biāo)準(zhǔn)。它可以用來在較短距離內(nèi)取代目前多種線纜連接方案，穿透墻壁等障礙，通過統(tǒng)一的短距離無線鏈路，在各種數(shù)字設(shè)備之間實現(xiàn)靈活、安全、低成本、小功耗的話音和數(shù)據(jù)通信。藍(lán)牙作為一種新興的短距離無線通信技術(shù)已經(jīng)在各個領(lǐng)域得到廣泛應(yīng)用，它提供低成本、低功耗、近距離的無線通信，構(gòu)成固定與移動設(shè)備通信環(huán)境中的個人網(wǎng)絡(luò)，使得近距離內(nèi)各種信息設(shè)備能夠?qū)崿F(xiàn)無縫資源共享。藍(lán)牙設(shè)備應(yīng)具有互操作性，即任何藍(lán)牙設(shè)備之間都應(yīng)能夠?qū)崿F(xiàn)互通互連，這包括硬件和軟件。設(shè)計協(xié)議和協(xié)議棧的主要原則是盡可能地利用現(xiàn)有各種高層協(xié)議，保證現(xiàn)有協(xié)議與藍(lán)牙技術(shù)的融合以及各種應(yīng)用之間的互通性；充分利用兼容藍(lán)牙技術(shù)規(guī)范的軟硬件系統(tǒng)和藍(lán)牙技術(shù)規(guī)范的開放性，便于開發(fā)新的應(yīng)用。具體的協(xié)議按SIG的需要分為4層：核心協(xié)、RFCOMM電纜替代協(xié)議、TCS電話控制協(xié)議以及與Internet相關(guān)的高層協(xié)議由于藍(lán)牙通信標(biāo)準(zhǔn)是以無線電波作為媒介，第三方可能輕易截獲信息，所以藍(lán)牙技術(shù)必須采取一定的安全保護(hù)機制，尤其在電子交易應(yīng)用時。為了提供使用的安全性和信息的可信度，系統(tǒng)必須在應(yīng)用層和鏈路層提供安全措施。由于市場需求，越來越多的藍(lán)牙硅片即將投入生產(chǎn)。旅館、郵局、高爾夫球場、飛機場、零售商場、會議中心和商業(yè)領(lǐng)域都在采用藍(lán)牙技術(shù)。BluetoothSiG現(xiàn)已擁有2400家會員公司，預(yù)計2015年藍(lán)牙芯片將達(dá)14億片，應(yīng)用機器近7億臺。暢游在藍(lán)牙技術(shù)的夢想中，你會發(fā)現(xiàn)藍(lán)牙技術(shù)無所不能。稍稍關(guān)注一下網(wǎng)絡(luò)高科技市場，就會發(fā)現(xiàn)藍(lán)牙技術(shù)從誕生的那一天起，就一直被人們寄予了極高的期望。相信隨著科技的進(jìn)一步發(fā)展，藍(lán)牙技術(shù)必將獲得更加廣泛的應(yīng)用。TheAdvantagesofSDHTheadvantagesofSDHaremainlyreflectedinthefollowing:Lowernetworkelementcosts:Withacommonstandard,compatibleequipmentwillbeavailablefrommanyvendors.Inahighlycompetitivemarketpriceswillbevaryattractive.Betternetworkmanagement:Withbetternetworkmanagement,operatorswillbeabletomoreefficientlyusethenetworkandprovidebetterservice.TheconceptofTMN(TelecomManagementNetwork)isunderstudybyCCITT.SomeTMNstandardsdefiningmanagementsysteminterfacesalreadyexist.Fasterprovisioning:Ifnewcircuitscanbesoftwaredefinedtouseexistingsparebandwidththenprovisioningwillbemuchfaster.Theonlynewconnectionneededwillbefromthecustomer'spremisestothenearestnetworkaccessnode.Betternetworkutilization:Withtotalcontrolofroutingcustomercircuitscanbe"groomed"or"hubbed"tomakebestuseofnetworkresources.Typically,allspeechcarryingcircuitsmaybesplitfromdatacircuitsandroutedforminimumdelay.Datacircuits,dependingonthetype,maybe"hubbed"toaparticularnetworkDXCwiththelevelofcross-connectneeded.Betternetworksurvivability:With"real-time"reroutingpossible,thenetwork'sOperationSupportSystemwillbeabletotakecareoffailurebyreprogrammingcircuitpaths.Thebuilt-inprotectionandreportingsystemswillautomaticallytakecareofsimpletransmissionfailures.Simplerhandover:Ifallnetworksuseequipmentconformingtothesamestandard,thehandoverofcircuitsatthe"networknodeinterface"shouldbetroublefree.Supportoffutureservices:Lookingtothefuture,theSDHdesignwillcaterfornewserviceslikeHighDefinitionTV,WideAreaNetworkbackbonenetworks,BroadbandISDNandnewbandwidth-on-demandservices.AstheSDHoperatorwillhavetotalcontrolofbandwidthallocation,anynewservicewillbesimpletooperation.SDH的優(yōu)勢SDH的優(yōu)勢主要體現(xiàn)在以下：低成本的網(wǎng)絡(luò)元素:普通標(biāo)準(zhǔn)、兼容的設(shè)備有利于很多廠商，在一個高度競爭的市場價格里將會變得更有吸引力。.更好的網(wǎng)絡(luò)管理:以更好的網(wǎng)絡(luò)管理、經(jīng)營者能夠更有效地利用網(wǎng)絡(luò)，提供更好的服務(wù)。這個概念在國際電報電話咨詢委員會研究TMN）。有些TMN標(biāo)準(zhǔn)接口定義管理系統(tǒng)已存在。設(shè)置:如果新電路的速度可以使用現(xiàn)有軟件設(shè)置將多余的帶寬就快得多。唯一的新連接需要將從客戶的場所的網(wǎng)絡(luò)接入節(jié)點。更好的網(wǎng)絡(luò)利用：與客戶可培訓(xùn)或套充分利用網(wǎng)絡(luò)資源。一般來說、所有的言論可能套攜帶電路與一個特定的網(wǎng)絡(luò)DXC現(xiàn)有水平的需要。更好的網(wǎng)絡(luò)生存性:讀改道,網(wǎng)絡(luò)運營支持系統(tǒng)能夠照顧失敗重整電路的路徑。內(nèi)置的保護(hù)和報告系統(tǒng)會自動照顧簡單的傳輸失敗如果所有的網(wǎng)絡(luò)的簡單回歸使用設(shè)備符合標(biāo)準(zhǔn)的回歸,在網(wǎng)絡(luò)節(jié)點接口電路應(yīng)該免除麻煩未來的支持服務(wù):展望未來,SDH設(shè)計迎合新的服務(wù)如高清晰度電視、大面積的主十網(wǎng)網(wǎng)絡(luò)、寬帶ISDN和新的寬帶ISDN和新bandwidth-on-demand服務(wù)。作為SDH運營商將會完全控制帶寬分配，任何新聞服務(wù)成為簡單的操作。TCP/IPReferenceModelTheTCP/IPmodelhasfourlayers:theapplicationlayer,thetransportlayer,theinternetlayer,andthenetworkaccesslayer.ThedesignersofTCP/IPfeltthatthehigher-levelprotocolsshouldincludethesessionandpresentationlayerdetails.Theysimplycreatedanapplicationlayerthathandleshigh-levelprotocols,issuesofrepresentation,encoding,anddialogcontrol.TheTCP/IPcombinesallapplication-relatedissuesintoonelayer,andensuresthisdataisproperlypackagedforthenextlayer.Thisisalsoreferredtoastheprocesslayer.Thetransportlayertypicallydealswiththeissuesofthereliability,flowcontrol,andretransmission.Oneofitsprotocols,thetransmissioncontrolprotocol(TCP),providesexcellentandflexiblewaystocreatereliable,well-flowing,networkcommunications.TCPisaconnection-orientedprotocol.Itsupportsdialoguesbetweensourceanddestinationwhilepackagingapplicationlayerinformationintounitscalledsegments.Connection-orienteddoesnotmeanthataphysicalcircuitexistsbetweenthecommunicatingcomputers(thatwouldbecircuitswitching).ItdoesmeanthatLayer4segmentsmusttravelbackandforthbetweentwohoststosetupalogicalconnectionbeforedatacanbesent.Thislayerisalsosometimescalledthehost-to-hostlayer.Thepurposeoftheinternetlayeristosendsourcepacketsfromanynetworkontheinternetworkandhavethemarriveatthedestinationindependentofthepathandnetworkstheytooktogetthere.ThespecificprotocolthatgovernsthislayeriscalledtheInternetProtocol(IP).Bestpathdeterminationandpacketswitchingoccuratthislayer.Thinkofitintermsofthepostalsystem.Whenyoumailaletter,youdonotknowhowitgetsthere(therearevariouspossibleroutes),butyoudocarethatitarrives.Thenameofthislayerisbroadandsomewhatconfusing.Italsoiscalledthehost-to-networklayer.Sometimes,it’sshownastwolayers,asintheOSImodel.Thenetworkaccesslayerisconcernedwithalltheissuesth