通信网络实验报告
实验一隐终端和暴露终端问题分析
一、实验目的
1、了解无线网络中的载波检测机制；
2、熟悉节点的传输范围、冲突干扰范围、载波检测范围和噪声干扰范围的概念；
3、了解载波检测接入体制中存在的隐终端问题和暴露终端问题；
4、结合仿真实验分析载波检测无线网络中的隐终端问题和暴露终端问题。
二、实验结果
Node: 1, Layer: AppCbrClient, (0) Server address: 2
Node: 1, Layer: AppCbrClient, (0) First packet sent at [s]: 0.000000000
Node: 1, Layer: AppCbrClient, (0) Last packet sent at [s]: 99.990000000
Node: 1, Layer: AppCbrClient, (0) Session status: Not closed
Node: 1, Layer: AppCbrClient, (0) Total number of bytes sent: 5120000
Node: 1, Layer: AppCbrClient, (0) Total number of packets sent: 10000
Node: 1, Layer: AppCbrClient, (0) Throughput (bits per second): 409600
Node: 2, Layer: AppCbrServer, (0) Client address: 1
Node: 2, Layer: AppCbrServer, (0) First packet received at [s]: 0.007438001 Node: 2, Layer: AppCbrServer, (0) Last packet received at [s]: 99.999922073 Node: 2, Layer: AppCbrServer, (0) Average end-to-end delay [s]: 0.739902205 Node: 2, Layer: AppCbrServer, (0) Session status: Not closed
Node: 2, Layer: AppCbrServer, (0) Total number of bytes received: 4975616 Node: 2, Layer: AppCbrServer, (0) Total number of packets received: 9718 Node: 2, Layer: AppCbrServer, (0) Throughput (bits per second): 398078 Node: 3, Layer: AppCbrClient, (0) Server address: 4
Node: 3, Layer: AppCbrClient, (0) First packet sent at [s]: 0.000000000
Node: 3, Layer: AppCbrClient, (0) Last packet sent at [s]: 99.990000000
Node: 3, Layer: AppCbrClient, (0) Session status: Not closed
Node: 3, Layer: AppCbrClient, (0) Total number of bytes sent: 5120000
Node: 3, Layer: AppCbrClient, (0) Total number of packets sent: 10000
Node: 3, Layer: AppCbrClient, (0) Throughput (bits per second): 409600
Node: 4, Layer: AppCbrServer, (0) Client address: 3
Node: 4, Layer: AppCbrServer, (0) First packet received at [s]: 0.003058001
Node: 4, Layer: AppCbrServer, (0) Last packet received at [s]: 99.993058001
Node: 4, Layer: AppCbrServer, (0) Average end-to-end delay [s]: 0.003119031 Node: 4, Layer: AppCbrServer, (0) Session status: Not closed
Node: 4, Layer: AppCbrServer, (0) Total number of bytes received: 5120000
Node: 4, Layer: AppCbrServer, (0) Total number of packets received: 10000
Node: 4, Layer: AppCbrServer, (0) Throughput (bits per second): 409612
三、实验结果分析
通过仿真结果可以看出，节点2无法收到数据。由于节点3是节点1的一个隐终端，节点1无法通过物理载波检测侦听到节点3的发送，且节点3在节点2的传输范围外，节点3无法通过虚拟载波检测延迟发送，所以在节点1传输数据的过程中，节点3完成退避发送时将引起冲突。
四、思考题
1、RTS/CTS能完全解决隐终端问题吗？如果不能，请说明理由。
从理论分析上看，RTS/CTS协议似乎可以完全解决数据链隐藏终端问题，然而在实际网络中并非如此，尤其是在AdHoc 网络中。以节点为中心，存在发送区域和干扰区域。在发送区域内，在没有干扰的情况下，数据包可正常收发；该区域的大小由站点的功率等参数确定，可视为定值。干扰区域是相对于接受节点而言的，在该区域内，节点可以受到来自非相关节点发送的数据的干扰，造成冲突、丢包。RTS/CTS对隐藏终端问题的屏蔽实际上是建立在两区域相等的基础上的，即所有的隐藏终端都位于接受节点发送范围内。此中假设并不成立，干扰区域与收发节点间距有关。
实验二无线局域网DCF协议饱和吞吐量验证
一、实验目的
1、了解IEEE 802.11 DCF 协议的基本原理。
2、理解网络饱和吞吐量的概念。
3、通过仿真对DCF协议饱和吞吐量的二维马尔可夫链模型进行验证。
二、实验结果
Node: 1, Layer: AppCbrClient, (4) Server address: 55
Node: 1, Layer: AppCbrClient, (4) First packet sent at [s]: 0.000000000
Node: 1, Layer: AppCbrClient, (4) Last packet sent at [s]: 99.990000000
Node: 1, Layer: AppCbrClient, (4) Session status: Not closed
Node: 1, Layer: AppCbrClient, (4) Total number of bytes sent: 5120000
Node: 1, Layer: AppCbrClient, (4) Total number of packets sent: 10000
Node: 1, Layer: AppCbrClient, (4) Throughput (bits per second): 409600
Node: 1, Layer: AppCbrClient, (3) Server address: 54
Node: 1, Layer: AppCbrClient, (3) First packet sent at [s]: 0.000000000 Node: 1, Layer: AppCbrClient, (3) Last packet sent at [s]: 99.990000000 Node: 1, Layer: AppCbrClient, (3) Session status: Not closed
Node: 1, Layer: AppCbrClient, (3) Total number of bytes sent: 5120000 Node: 1, Layer: AppCbrClient, (3) Total number of packets sent: 10000 Node: 1, Layer: AppCbrClient, (3) Throughput (bits per second): 409600 Node: 1, Layer: AppCbrClient, (2) Server address: 53
Node: 1, Layer: AppCbrClient, (2) First packet sent at [s]: 0.000000000 Node: 1, Layer: AppCbrClient, (2) Last packet sent at [s]: 99.990000000 Node: 1, Layer: AppCbrClient, (2) Session status: Not closed
Node: 1, Layer: AppCbrClient, (2) Total number of bytes sent: 5120000 Node: 1, Layer: AppCbrClient, (2) Total number of packets sent: 10000 Node: 1, Layer: AppCbrClient, (2) Throughput (bits per second): 409600 Node: 1, Layer: AppCbrClient, (1) Server address: 52
Node: 1, Layer: AppCbrClient, (1) First packet sent at [s]: 0.000000000 Node: 1, Layer: AppCbrClient, (1) Last packet sent at [s]: 99.990000000 Node: 1, Layer: AppCbrClient, (1) Session status: Not closed
Node: 1, Layer: AppCbrClient, (1) Total number of bytes sent: 5120000 Node: 1, Layer: AppCbrClient, (1) Total number of packets sent: 10000 Node: 1, Layer: AppCbrClient, (1) Throughput (bits per second): 409600 Node: 1, Layer: AppCbrClient, (0) Server address: 51
Node: 1, Layer: AppCbrClient, (0) First packet sent at [s]: 0.000000000 Node: 1, Layer: AppCbrClient, (0) Last packet sent at [s]: 99.990000000 Node: 1, Layer: AppCbrClient, (0) Session status: Not closed
Node: 1, Layer: AppCbrClient, (0) Total number of bytes sent: 5120000 Node: 1, Layer: AppCbrClient, (0) Total number of packets sent: 10000 Node: 1, Layer: AppCbrClient, (0) Throughput (bits per second): 409600 Node: 51, Layer: AppCbrServer, (0) Client address: 1
Node: 51, Layer: AppCbrServer, (0) First packet received at [s]: 0.003056858 Node: 51, Layer: AppCbrServer, (0) Last packet received at [s]: 99.995493030 Node: 51, Layer: AppCbrServer, (0) Average end-to-end delay [s]: 0.351972641 Node: 51, Layer: AppCbrServer, (0) Session status: Not closed
Node: 51, Layer: AppCbrServer, (0) Total number of bytes received: 5102592 Node: 51, Layer: AppCbrServer, (0) Total number of packets received: 9966 Node: 51, Layer: AppCbrServer, (0) Throughput (bits per second): 408219 Node: 52, Layer: AppCbrServer, (1) Client address: 1
Node: 52, Layer: AppCbrServer, (1) First packet received at [s]: 0.006449537
Node: 52, Layer: AppCbrServer, (1) Last packet received at [s]: 99.998965709 Node: 52, Layer: AppCbrServer, (1) Average end-to-end delay [s]: 0.355584451 Node: 52, Layer: AppCbrServer, (1) Session status: Not closed
Node: 52, Layer: AppCbrServer, (1) Total number of bytes received: 5102592 Node: 52, Layer: AppCbrServer, (1) Total number of packets received: 9966 Node: 52, Layer: AppCbrServer, (1) Throughput (bits per second): 408233 Node: 53, Layer: AppCbrServer, (2) Client address: 1
Node: 53, Layer: AppCbrServer, (2) First packet received at [s]: 0.010001809 Node: 53, Layer: AppCbrServer, (2) Last packet received at [s]: 99.992000125 Node: 53, Layer: AppCbrServer, (2) Average end-to-end delay [s]: 0.358534977 Node: 53, Layer: AppCbrServer, (2) Session status: Not closed
Node: 53, Layer: AppCbrServer, (2) Total number of bytes received: 3926016 Node: 53, Layer: AppCbrServer, (2) Total number of packets received: 7668 Node: 53, Layer: AppCbrServer, (2) Throughput (bits per second): 314112 Node: 54, Layer: AppCbrServer, (3) Client address: 1
Node: 54, Layer: AppCbrServer, (3) First packet received at [s]: 0.013774900 Node: 54, Layer: AppCbrServer, (3) Last packet received at [s]: 0.773715844 Node: 54, Layer: AppCbrServer, (3) Average end-to-end delay [s]: 0.184107930 Node: 54, Layer: AppCbrServer, (3) Session status: Not closed
Node: 54, Layer: AppCbrServer, (3) Total number of bytes received: 22016 Node: 54, Layer: AppCbrServer, (3) Total number of packets received: 43 Node: 54, Layer: AppCbrServer, (3) Throughput (bits per second): 1761
Node: 55, Layer: AppCbrServer, (4) Client address: 1
Node: 55, Layer: AppCbrServer, (4) First packet received at [s]: 0.017127686 Node: 55, Layer: AppCbrServer, (4) Last packet received at [s]: 0.777148630 Node: 55, Layer: AppCbrServer, (4) Average end-to-end delay [s]: 0.187729553 Node: 55, Layer: AppCbrServer, (4) Session status: Not closed
Node: 55, Layer: AppCbrServer, (4) Total number of bytes received: 22016 Node: 55, Layer: AppCbrServer, (4) Total number of packets received: 43 Node: 55, Layer: AppCbrServer, (4) Throughput (bits per second): 1761
三、实验结果分析
各发送节点发包间隔较大，当网络中发送节点较少时，网络还未饱和。逐渐往网络中增加负载，网络总吞吐量逐渐增大，之后，网络吞吐量逐渐趋向于平稳，此时，网络即达到了饱和状态。
四、思考题
1、总结IEEE 802.11DCF协议饱和吞吐量和哪些因素有关。
任选一个时隙，网络中有节点在发送数据的概率
当有节点在发送数据包时，数据包发送成功的概率
数据包发送成功和发送失败所需的时间
2、为什么在数据包长度较长时，采用RTS/CTS模式更合理？
"隐藏终端"多发生在大型单元中（一般在室外环境），这将带来效率损失，并且需要错误恢复机制。当需要传送大容量文件时，尤其需要杜绝"隐藏终端"现象的发生。
实验三动态源路由协议路由选择验证
一、实验目的
1、了解DSR路由协议的优缺点。
2、理解DSR路由协议中路由发现过程和路由维护过程。
3、掌握DSR路由协议性能的仿真分析方法。
二、实验结果
Time(s): 2.000001000, Node: 1, Route path: 2 Time(s): 3.000001000, Node: 1, Route path: 2 Time(s): 4.000001000, Node: 1, Route path: 2 Time(s): 5.000001000, Node: 1, Route path: 2 Time(s): 6.000001000, Node: 1, Route path: 2 Time(s): 7.000001000, Node: 1, Route path: 2 Time(s): 8.000001000, Node: 1, Route path: 4-2 Time(s): 9.000001000, Node: 1, Route path: 4-2 Time(s): 10.000001000, Node: 1, Route path: 4-2 Time(s): 11.000001000, Node: 1, Route path: 4-2 Time(s): 12.000001000, Node: 1, Route path: 4-2 Time(s): 13.000001000, Node: 1, Route path: 4-2 Time(s): 14.000001000, Node: 1, Route path: 4-2 Time(s): 15.000001000, Node: 1, Route path: 4-2 Time(s): 16.000001000, Node: 1, Route path: 4-2 Time(s): 17.000001000, Node: 1, Route path: 4-2 Time(s): 18.000001000, Node: 1, Route path: 4-2 Time(s): 19.000001000, Node: 1, Route path: 4-2 Time(s): 20.000001000, Node: 1, Route path: 4-2 Time(s): 21.000001000, Node: 1, Route path: 4-2 Time(s): 22.000001000, Node: 1, Route path: 4-2 Time(s): 23.000001000, Node: 1, Route path: 4-2 Time(s): 24.000001000, Node: 1, Route path: 4-2 Time(s): 25.000001000, Node: 1, Route path: 4-2 Time(s): 26.000001000, Node: 1, Route path: 4-2 Time(s): 27.000001000, Node: 1, Route path: 4-2 Time(s): 28.000001000, Node: 1, Route path: 4-2 Time(s): 29.000001000, Node: 1, Route path: 4-2 Time(s): 30.000001000, Node: 1, Route path: 4-2 Time(s): 31.000001000, Node: 1, Route path: 4-2 Time(s): 32.000001000, Node: 1, Route path: 4-2 Time(s): 33.000001000, Node: 1, Route path: 4-2 Time(s): 34.000001000, Node: 1, Route path: 4-2 Time(s): 35.000001000, Node: 1, Route path: 4-2 Time(s): 36.000001000, Node: 1, Route path: 4-2 Time(s): 37.000001000, Node: 1, Route path: 4-2 Time(s): 38.000001000, Node: 1, Route path: 5-4-2
Time(s): 40.000001000, Node: 1, Route path: 5-4-2 Time(s): 41.000001000, Node: 1, Route path: 5-4-2 Time(s): 42.000001000, Node: 1, Route path: 5-4-2 Time(s): 43.000001000, Node: 1, Route path: 5-4-2 Time(s): 44.000001000, Node: 1, Route path: 5-4-2 Time(s): 45.000001000, Node: 1, Route path: 5-4-2 Time(s): 46.000001000, Node: 1, Route path: 5-4-2 Time(s): 47.000001000, Node: 1, Route path: 5-4-2 Time(s): 48.000001000, Node: 1, Route path: 5-4-2 Time(s): 49.000001000, Node: 1, Route path: 5-4-2 Time(s): 50.000001000, Node: 1, Route path: 5-4-2 Time(s): 51.000001000, Node: 1, Route path: 5-4-2 Time(s): 52.000001000, Node: 1, Route path: 5-4-2 Time(s): 53.000001000, Node: 1, Route path: 5-4-2 Time(s): 54.000001000, Node: 1, Route path: 5-4-2 Time(s): 55.000001000, Node: 1, Route path: 5-4-2 Time(s): 56.000001000, Node: 1, Route path: 5-4-2 Time(s): 57.000001000, Node: 1, Route path: 5-4-2 Time(s): 58.000001000, Node: 1, Route path: 5-4-2 Time(s): 59.000001000, Node: 1, Route path: 5-4-2 Time(s): 60.000001000, Node: 1, Route path: 5-4-2 Time(s): 61.000001000, Node: 1, Route path: 5-4-2 Time(s): 62.000001000, Node: 1, Route path: 5-4-2 Time(s): 63.000001000, Node: 1, Route path: 5-4-2 Time(s): 64.000001000, Node: 1, Route path: 5-4-2 Time(s): 65.000001000, Node: 1, Route path: 5-4-2 Time(s): 66.000001000, Node: 1, Route path: 5-4-2 Time(s): 67.000001000, Node: 1, Route path: 5-4-2 Time(s): 68.000001000, Node: 1, Route path: 3-2 Time(s): 69.000001000, Node: 1, Route path: 3-2 Time(s): 70.000001000, Node: 1, Route path: 3-2 Time(s): 71.000001000, Node: 1, Route path: 3-2 Time(s): 72.000001000, Node: 1, Route path: 3-2 Time(s): 73.000001000, Node: 1, Route path: 3-2 Time(s): 74.000001000, Node: 1, Route path: 3-2 Time(s): 75.000001000, Node: 1, Route path: 3-2 Time(s): 76.000001000, Node: 1, Route path: 3-2