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1、Cisco城域接入網(wǎng)絡(luò)解決方案 ---CableAgendaCiscoCATVSolutionProductUpdateTheCiscoAdvantageNodeHeadend/RegionalDataCenterNodeNodeHubHubNodeNodeNodeHubNodeCOAXTapNodeNodeDrop600-2000HomesDropHomeArchitectureDistributionArchitectureHUBArchitectureCable系統(tǒng)一個(gè)有限電視網(wǎng)的5個(gè)主要部件
2、體系結(jié)構(gòu)部件頭端中繼電纜鄰域中的分布電纜分接電纜終端設(shè)備(電視、電纜調(diào)制解調(diào)器、機(jī)頂盒等)電纜系統(tǒng)拓?fù)?(光纖節(jié)點(diǎn))從/到頭端級(jí)聯(lián)中一般不到5個(gè)放大器一個(gè)節(jié)點(diǎn)一般支持200--2000個(gè)家庭樹和枝杈系統(tǒng)頭端光纖節(jié)點(diǎn)中繼電纜激活一個(gè)雙向網(wǎng)絡(luò)RHE (地區(qū)頭端)其他來(lái)源Modulator andScramblerForEach ChannelFiberRack TX/RX本地頭端HFCLHELHE光纖雙向LCUpConverteruBR7246光纖節(jié)點(diǎn)電纜調(diào)制解調(diào)器TapTVReceiverModula
3、tor andScramblerReceiverHub示意圖FastEther/Gig-EtherModulatorsAMandDigitalChannelsUniversalBroadbandRouterRFRFMCNSDownMCNSUpOC-48SONET/SDH/...Upconverter，射頻調(diào)制HL混頻器7204MPS有線電視網(wǎng)(HFC)的接入模擬電話UBR7246CableRouterHFC數(shù)據(jù)網(wǎng)CableModemUBR924/SmallCablerouter/機(jī)頂盒銅軸電纜5-4
4、2MHz銅軸電纜以太網(wǎng)PCTVTV下行27-40Mbps/Modem上行nx(2.5-5Mbps)/Modem,n=1,2,4,6uBR7246CombinerCHACHBCHCCHDLocalFeedCombinerEachsetofhomesseestheirprimarydownstreamchannelDownstream:FrequencyConverter有線電視網(wǎng)(HFC)的接入HFCuBR7246UpstreamterminateonrespectiveLineCardUpstrea
5、ms:有線電視網(wǎng)(HFC)的接入HFCSampleCablePlantLayoutupstreamdownstreamfutureDOCSISOOBDAVICAnalogTVDigitalTV0Mhz750Mhz42MhzNote:thefrequenciesforanalogvs.digitalarearbitrary;onlymust-carrylawsdictatechannelplacement.CableChannel?NTSC-USA-6MHz-27/36Mbit/sec?PAL-Eur
6、ope-8MHz-36/46Mbit/sec?64/256QAM-RFModulateddigitalsignal-QuadratureAmplitudeDataRatesFreqRangeMHzTDMACarrierQAM-2568b/SymQAM-646b/SymQAM-164b/SymQPSK2b/Sym54-86054-86054-86054-8605-425-425-425-42ChannelWidthMHz68681.63.21.63.2BaudRateMSps5.36057.155.0
7、576.741.282.561.282.56RawBitRateMbps42.8857.230.3440.445.1210.242.565.12PayloadRateMbps~38~57~27~36~4.6~9~2.3~4.6目前使用DOCSISDataOverCableNetworksOSIHigherLayersTransportNetworkDataLinkPhysicalApplicationsTCPorUDPIPIEEE802.2DOCSISMACHFCUpStreamTDMA(Mini-
8、Slots)5-65MHz(QPSKorQAM-16)DownStreamTDMA(MPEG)Band6MHz(QAM-64orQAM-256)DOCSISControlMessagesCASEBackboneDataCenter/HeadendVoDServersCiscoCatalyst6000CiscoGSR12000MiddlewareServerCiscoCableTroubleshooterCiscoCacheEngineSatelliteAntennaC
