atm技術(shù)與骨干網(wǎng)技術(shù)(文件)
【正文】 22ATM適配層（ AAL)ATM Adaptation Layer (AAL)ATM LayerPhysical Layer 業(yè)務(wù)參數(shù) A類 B類 C類 D類時間關(guān)系 實時 非實時比特率 固定 可變連接方式 面向連接 無連接AAL類型 AAL 1 AAL 2 AAL 3 /AAL 4 AAL 5用戶業(yè)務(wù)舉例同步網(wǎng)電路仿真壓縮圖象視頻聲頻 Frame Relay IP23AAL5SARSublayerConvergence Sublayer PDUPayload FrameAAL5 SAR PDUSAR PDUSAR PDUSAR PDUATM Cell0x0ATM CellATM CellATM Cell0x00x00x124AAL5的幀與信元格式AAL5 CPCS PDU Frame = n x 48 bytes065535 bytesPayload Length CRC32Control(CPI and UU)4 bytes2byte 2 bytesPADAAL5 CPCS PDU TrailerUser DataAAL5 SAR PDU = 1 Cell PayloadSARPDU Payload = 48 bytes047bytes25IPoverATM重疊方式： 典型設(shè)備： Cisco2500/2600 以太網(wǎng)交換機(jī) 10ATM技術(shù)? A promise for voice, data, and video ? Hardwarebased cell relay? Larger frames are segmented and reassembled at ATM endpoints? Can span both LAN and WAN? Scales from a few Mbps to multiGbps? QoS defined/negotiated when initial connection is madeVoice Video DataATM cells48octet PayloadATM 53octet cells areswitched in hardware11ATM應(yīng)用12ATM體系結(jié)構(gòu)? 高層? ATM適配層（ AAL） CS: 匯聚子層 SAR： 拆拼子層? ATM層? 物理層1第七章 無需 ARP 。STS3 OC3 STM1 STS24 OC24 STM8 18:10:0918:10:0918:101/31/2023 6:10:09 PM1以我獨沈久，愧君相 見頻 。 31 一月 20236:10:09 下午 18:10:09一月
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