计算机专业英语Chapter7课件

1、内容正文Network TopologySLIDING WINDOW PROTOCOLS阅读材料IPv6Router7-1 Network Topology Network topologies are categorized into the following basic types: Bus topologyStar topology Ring topology Tree topology Mesh topologyKey Wordstopology n.拓扑结构layout n.布局hybrids n.合成物ethernet n.以太网络repeater n.中继器token ring

2、令牌环backbone network 骨干网络protocol n.协议Key Wordscoaxial adj.同轴的fault tolerance 误差，错误范围（容许值）concentrator n.集线器unshielded twisted pair 屏蔽双绞线NotesA bus topology becomes slow by heavy network traffic with a lot of computer because networks do not coordinate with each other to reserve times to transmit.当一个

3、总线拓扑结构里有很多的计算机的时候，由于网络无法协调每个计算机以保留传输时间，严重的网络拥塞会导致总线速度变慢。One aspect of the Ethernet protocol requires that a signal sent out on the network cable reach every part of the network within a specified length of time. Each concentrator or repeater that a signal goes through adds a small amount of time.以太网

4、协议的一个方面要求一个发送到网络上的信号须在预定的时间内到达网络的每一个角落。信号经过的每个网络集线器或中继器都会增加一个小的延时。7-2 SLIDING WINDOW PROTOCOLSKey Wordsdata frame 数据帧full-duplex 全双工acknowledgement确认ack field应答域piggybacking 捎带传输data link layer数据链路层Key Wordsoutboundn. 输出sequence number 序号shut off关闭NotesWhen a data frame arrives, instead of immediate

5、ly sending a separate control frame, the receiver restrains itself and waits until the network layer passes it the next packet.当数据帧到达时，接收者并不立即发送一个独立的控制帧，而是保留直到网络层传来下一个包。NotesAlthough these protocols give the data link layer more freedom about the order in which it may send and receive frames, we hav

6、e definitely not dropped the requirement that the protocol must deliver packets to the destination network layer in the same order they were passed to the data link layer on the sending machine.尽管这些协议使得数据链路层在发送和接收帧的顺序上有了更多的自由，但是我们绝对没有放弃对此的要求，即协议发送包到目的地网络层的顺序必须和它们在发送方传到数据链路层的顺序一致。Reading Material 1 I

7、PV6 IntroductionIPv6 Network ArchitectureIPv6 Communication FundamentalsInternetwork CommunicationsReading Material 2 Router Exercises Network topologies are categorized into the following basic types: _, _, _, _, and _.A _ topology connects computers along a single or more cable to connect linearly

8、.Ethernet 10BaseT is a network based on the _ topology.The ring topology is commonly used in _ networks that the ring of such network is concentrated inside a device called a Multistation Access Unit (MAU) and fiber Distributed Data Interface (FDDI) networks.The _ topology provides fault tolerance.T

9、he way of achieving _ transmission is to have two separate communication channels and use each one for simplex data traffic (in different directions).The technique of temporarily delaying outgoing acknowledgements so that they can be hooked onto the next outgoing data frame is known as _.In all sliding window protocols, each outbound frame