试思科网络技术验四.doc

LAB 4 Cabling LANs and WANsPART 1 RepeatersObjective: Create a simulated network topology Apply IP addresses to workstations Be familiar with the function of a repeater Understand the Four Repeater Rule Test the simulated topology Step 1Create the topology shown in the diagram in Packet Tracer. After connecting all the devices, assign each PC with a valid IP address and subnet mask. (You can use any IP addresses as long as they belong to the same network.)Step 2a) Click on the Simulation tab to start creating a scenario.b) Add a packet and click on source PC 0 and then click on destination PC 1. Add another packet from PC 1 to PC 2.c) Click play to watch the simulation.d) Take note of the time it takes for each packet to reach its destination. (Having more repeaters between workstations adds latency to the packets.)Step 3a) Click once on the arrow on the left of the play button to go back one second (The number in the Time box should be “6”)b) Add a packet from PC 2 to PC 1.c) Click on the Topology tab. Remove a connection then add another repeater anywhere between Switch 0 and PC 2. Re-connect the devices.d) Click on the Simulation and hit the play button to watch the simulation. (Latency results in collision.)PART 2 Repeaters and HubsInformation:1. This topology consists of 8 hosts along with 2 hubs and 1 repeater in the network. Tips:a) The Packet Tracer “i” located on the upper right of each page and device will give information pertaining to that certain device or topology.b) In simulation, the “i” next to the scenario drop down list will give information about the specific scenario.c) In simulation, clicking on the packets will show OSI layer information.Procedures:a) In the topology mode, add three (3) additional repeaters between the two (2) hubs.b) In simulation mode, create a new scenario.c) Send a packet from PC4 to PC0 and a packet from PC5 to PC1 at different times so that the packets will not collide.d) Before running the simulation, click on the individual packets on PC4 and PC5 to review the packet and OSI information. Next, run the simulation.e) After the first simulation, repeat step 3 except the packets does collide this time. Then repeat step 4.f) After the packets arrive to Hub1, click on the packet that leaves Hub1 and propagates to Repeater0.Questions:a) What is the purpose of a hub and repeater in this network?集线器：对接收到的信号进行再生整形放大，以扩大网络的传输距离，同时把所有节点集中在以它为中心的节点上；中继器：主要功能是通过对数据信号的重新发送或者转发，来扩大网络传输的距离。b) What type of medium is being used to connect the hosts to the hubs and the repeater to the hubs? twisted pairc) How many collision domain(s) does this network contain?2个冲突域PART 3 WirelessInformation:1. This topology consists of a workstation, a laptop, a server, a printer, and an access point. The entire network is wireless. Tips:a) The Packet Tracer “i” located on the upper right of each page and device will give information pertaining to that certain device or topology.b) In simulation, the “i” next to the scenario drop down list will give information about the specific scenario.c) In simulation, clicking on the packets will show OSI layer information.Procedures:a) Review Scenario 2 in simulation mode.b) Take into consideration that the connected devices doesnt have any idea that the collisions are occurring.c) What if the devices continue sending packets to each other indefinitely? A simulation can be seen by creating packets between the devices so that multiple collisions happen one after another. Think of the latency this type of situation creates.Questions:a) What types of signals are wireless connections capable of?语音和数据信号b) In what ways are access points related or different compared to other networking devices such as hubs and switches?般俗称为网络桥接器，顾名思义即是当作传统的有线局域网络与无线局域网络之桥梁，因此任何一台装有无线网卡之PC均可透过AP去分享有线局域网络甚至广域网络之资源。除此之外，AP本身又兼具有网管之功能，可针对接有无线网络卡之PC作必要之控管。c) What security issue(s) arises when using wireless connectivity?非授权用户的接入、信息泄露、信号干扰、伪装地址和拦截对话、高级攻击d) In what situations does wireless connectivity have an advantage over wired and vice versa?安装便捷、使用灵活、易于扩展PART 4 Bridges and SwitchesInformation:1. This topology consists of 14 hosts along with 4 switches and 2 bridges in the network. Tips:a) The Packet Tracer “i” located on the upper right of each page and device will give information pertaining to that certain device or topology.b) In simulation, the “i” next to the scenario drop down list will give information about the specific scenario.c) In simulation, clicking on the packets will show OSI layer information.d) In simulation, clicking on the bridges and switches will load up the MAC address tables.Procedures:a) In the topology mode, Switch0s Fast Ethernet port 6 is disabled. As a result, the link between Switch0 and Bridge0 is down.b) Still in topology mode, click on Switch0 and then click on Fast Ethernet port 6. Enable the port by turning it on.c) Now go into simulation mode. As you may notice the link that was just enabled, has just disabled itself. This effect is due to the loop that is created in the topology and the Spanning Tree Protocol prevents this loop from occurring.d) Send a packet from host Xc to host XX. Analyze the path the packet takes. Since the link from Switch0 and Bridge0 is down to prevent a loop, Switch3 must send the packet to Bridge1 who sends it to Switch2, who then sends it to Switch0 and finally ending up at host XX.e) Now, in topology mode, remove two of the bridges and create a connection between the isolated network segments so that packets can be sent amongst them.Questions:a) What is the purpose of a bridge and switch in this topology?网桥：网桥的功能在延长网络跨度上类似于中继器，然而它能提供智能化连接服务，即根据帧的终点地址处于哪一网段来进行转发和滤除。交换机：交换机的主要功能包括物理编址、网络拓扑结构、错误校验、帧序列以及流控。b) Which OSI layer(s) does a bridge and switch work on?数据链路层c) What are the benefits of using bridges and switches compared to repeaters and hubs?集线器的某个端口工作的时候其他所有端口都有名收听到信息，容易产生广播风暴。当网络较大的时候网络性能会受到很大的影响，换机就能够起到这种作用，当交换相工作的时候只有发出请求的端口和目的端口之间相互响应而不影响其他端口，那么交换机就能够隔离冲突域和有效地抑制广播风暴的产生。集线器不管有多少个端口，所有端口都共享一条带宽，在同一时刻只能有两个端口传送数据，其他端口只能等待；同时集线器只能工作在半双工模式下。而对于交换机而言，每个端口都有一条独占的带宽，当两个端口工作时并不影响其他端口的工作，同时交换机不但可以工作在半双工模式下也可以工作在全双工模式下。d) How many collision domain(s) does this network contain?20个冲突域PART 5 Building a peer to peer networkObjective: Create a simple peer-to-peer network between two PCs Apply IP addresses to workstations Test connectivity in the simulated topology Step 1a) Create the topology shown in the diagram in Packet Tracer.b) After connecting the devices, assign each PC with an IP address according to the information in the table below:ComputerIP AddressSubnet maskPC 0PC 1Step 2e) Click on the Simulation tab to start creating a scenario.f) Add a packet from PC 0 to PC 1.g) Click play to test the connectivity between the PCs.Step 3a) Click on the topology tab.b) Click on PC 0 and set it to half duplex (default is on auto negotiate).c) Do the same for PC 1.d) Click on the Simulation tab.e) Add a packet from PC 1 to PC 0.f) Click play to watch the simulation.g) Note that collision occurs on a half duplex connection (data is transmitted in one direction at a time) when two workstations send a signal at the same time.Step 3a) Click on the topology tab.b) Click on PC 0 and set it to full duplex.c) Do the same for PC 1.d) Click on the Simulation tab.e) Click play to watch the simulation.f) Note that collision does not occur on a full duplex connection (data is transmitted in two directions simultaneously).PART 6 Building a hub-based networkObjective: Create a simple network with two PCs using a hub Apply IP addresses to workstations Test connectivity in the simulated topology Step 1a) Create the topology shown in the diagram in Packet Tracer.b) After connecting the devices, assign each PC with an IP address according to the information in the table below:ComputerIP AddressSubnet maskPC 0PC 1Step 2a) Click on the Simulation tab to start creating a scenario.b) Add a packet from PC 0 to PC 1.c) Click play to watch the simulation.Step 3a) Click on the topology tab.b) Add another PC and connect it to the hub. Assign it with an IP address of and a subnet mask of .c) Click on the simulation tab and click play to watch the simulation again. (Hubs dont filter traffic. They forward packets to each workstation that is connected to them.)d) Add a packet from PC 0 to PC 1 and PC 2 to PC 0.e) Click play to watch the simulation. (Since hubs dont filter traffic, they permit collisions to occur.)PART 7 Building a switch-based network Objective: Create a simple network with two PCs using a switch Apply IP addresses to workstations Test connectivity in the simulated topology Step 1a) Create the topology shown in the diagram in Packet Tracer.b) After connecting the devices, assign each PC with an IP address according to the information in the table below:ComputerIP AddressSubnet maskPC 0PC 1Step 2a) Click on the Simulation tab to start creating a scenario.b) Add a packet from PC 0 to PC 1.c) Click play to watch the simulation.d) Click on the switch to view its MAC table. (PC 0 and PC 1s MAC addresses are in the table.)Step 3a) Click on the topology tab.b) Add another PC and connect it to the switch. Assign it with an IP address of and a subnet mask of.c) Click on the simulation tab and click play to watch the simulation again. (Switches choose the port to which the destination device is connected. They forward a packet only to its destination.)d) Click on the switch to view its MAC table again. PC 2s MAC address is now in the table. A switch learns the addresses of the devices connected to it and automatically puts it in the table.Step 4a) Add a packet from PC 0 to PC 1, PC 1 to PC 2