《计算机网络和 与因特网》课件第十五章局域网布线、物理拓扑和接口硬件.pptVIP

Computer Networks and Internets 《计算机网络与因特网》课件 林坤辉 PART II Packet Transmission Chapter 15 LAN Wiring, Physical Topology, and Interface Hardware 局域网布线、物理拓扑和接口硬件 15.2 Speeds of LANs and Computer计算机与局域网的速度 Each network technology specifies a rate at which data must be sent. Many LANs operate at a rate so fast that a computer’s CPU cannot process bits at network speed. The speed at which a network operates is usually fixed in the design---the speed does not depend on the CPU rates of the attached computers. 15.3 Network Interface Hardware  15.4 The Connection Between A NIC and A Network The type of connection used between a NIC and a network depends on the network technology. 15.5 Original Thick Ethernet Wiring 粗缆以太网布线 The shared medium consists of a thick coaxial cable. Each computer connected to the network requires a hardware device known as a transceiver(收发器) . The cable connecting a NIC to a transceiver is known as an Attachment Unit Interface(AUI). 15.6 Connection Multiplexing多路复用连接 Formally called 10Base5. A connection multiplexor allows multiple computers to attach to a single transceiver. A connection multiplexor is an electronic device designed to provide exactly the same signals as a conventional transceiver. 15.7 Thin Ethernet Wiring细缆以太网布线 Formally called 10Base2. Thinnet generally costs less. No external transceivers are needed. Thinnet does not use an AUI. Thinnet attaches directly to the back of each computer using a BNC connector. 10BASE-2连接示意图 15.8 Twisted Pair Ethernet 双绞线以太网 Formally called 10BaseT. The 10BaseT does not use a coaxial cable. The 10BaseT uses an electronic device known as Enthernet hub. The connection between a computer and the hub uses twisted pair wiring with RJ-45 connectors. 10BASE-T连接示意图 IEEE802.3 的三种接线方式 10BASE-FL连接示意图