IEEE802系列标准ieee802.org/FromWikipedia,thefreeencyclopediaJumpto:navigation,searchThisincludesalistofreferences,relatedreadingorexternallinks,butitssourcesremainunclearbecauseitlacksinlinecitations.Pleaseimprovethisbyintroducingmoreprecisecitationswhereappropriate.(April2009)IEEE802referstoafamilyofIEEEstandardsdealingwithlocalareanetworksandmetropolitanareanetworks.Morespecifically,theIEEE802standardsarerestrictedtonetworkscarryingvariable-sizepackets.(Bycontrast,incell-basednetworksdataistransmittedinshort,uniformlysizedunitscalledcells.Isochronousnetworks,wheredataistransmittedasasteadystreamofoctets,orgroupsofoctets,atregulartimeintervals,arealsooutofthescopeofthisstandard.)Thenumber802wassimplythenextfreenumberIEEEcouldassign,though“802”issomeassociatedwiththedatethefirstmeetingwasheld—February1980.TheservicesandprotocolsspecifiedinIEEE802maptothelowertwolayers(DataLinkandPhysical)oftheseven-layerOSInetworkingreferencemodel.Infact,IEEE802splitstheOSIDataLinkLayerintotwosub-layersnamedLogicalLinkControl(LLC)andMediaAccessControl(MAC),sothatthelayerscanbelistedlikethis:DatalinklayeroLLCSublayeroMACSublayerPhysicallayerTheIEEE802familyofstandardsismaintainedbytheIEEE802LAN/MANStandardsCommittee(LMSC).ThemostwidelyusedstandardsarefortheEthernetfamily,TokenRing,WirelessLAN,BridgingandVirtualBridgedLANs.AnindividualWorkingGroupprovidesthefocusforeacharea.Contents[hide]1Workinggroups2Seealso3References4Externallinks[edit]WorkinggroupsnamedescriptionnoteIEEE802.1Bridging(networking)andNetworkManagementIEEE802.2LogicallinkcontrolinactiveIEEE802.3EthernetIEEE802.4TokenbusdisbandedIEEE802.5DefinestheMAClayerforaTokenRinginactiveIEEE802.6MetropolitanAreaNetworksdisbandedIEEE802.7BroadbandLANusingCoaxialCabledisbandedIEEE802.8FiberOpticTAGdisbandedIEEE802.9IntegratedServicesLANdisbandedIEEE802.10InteroperableLANSecuritydisbandedIEEE802.11a/b/g/nWirelessLAN(WLAN)Mesh(Wi-Ficertification)IEEE802.12demandprioritydisbandedIEEE802.13Usedfor100BASE-XEthernetIEEE802.14CablemodemsdisbandedIEEE802.15WirelessPANIEEE802.15.1BluetoothcertificationIEEE802.15.2IEEE802.15andIEEE802.11coexistenceIEEE802.15.3High-RateWPANcertificationIEEE802.15.4Low-rateWPANcertificationIEEE802.15.5MeshnetworkingforWPANIEEE802.16BroadbandWirelessAccess(WiMAXcertification)IEEE802.16e(Mobile)BroadbandWirelessAccessIEEE802.16.1LocalMultipointDistributionServiceIEEE802.17ResilientpacketringIEEE802.18RadioRegulatoryTAGIEEE802.19CoexistenceTAGIEEE802.20MobileBroadbandWirelessAccessIEEE802.21MediaIndependentHandoffIEEE802.22WirelessRegionalAreaNetworkIEEE802.23EmergencyServicesWorkingGroupNew(March,2010)对于不同传输介质的不同局域网，IEEE局域网标准委员会定制了不同的标准，适用于不同的网络环境，IEEE802各标准之间的关系如图4-2所示。IEEE802标准主要包括几项（这些标准在物理层和MAC子层有区别，但在逻辑链路子层是兼容的）：①IEEE802.1标准，定义了局域网体系结构、网络互联，以及网络管理与性能测试。②IEEE802.2标准，定义了逻辑链路控制（LLC）子层的功能与服务。③IEEE802.3标准，定义了CSMA/CD总线介质访问控制子层和物理层规范。在物理层定义了4种不同介质的10Mb/s的以太网规范，包括10Base-5（粗同轴电缆）、10Base-2（细同轴电缆）、10Base-F（多模光纤）和10Base-T（无屏蔽双绞线UTP）。另外，到目前为止IEEE802.3工作组还开发了一系列标准，如下所示。•IEEE802.3u标准，百兆快速以太网标准，现已合并到IEEE802.3中。•IEEE802.3z标准，光纤介质千兆...