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计算机与通信网络实验报告

计算机与通信网络实验报告041220111 戴妍实验一隐终端与暴露终端问题分析一、实验设定:基本参数配置:仿真时长100s;随机数种子1;仿真区域2000x2000;节点数4。

节点位置配置:本实验用[1]、[2]、[3] 、[4]共两对节点验证隐终端问题。

节点[1]、[2]距离为200m,节点[3]、[4]距离为200m,节点[2]、[3]距离为370m。

业务流配置:业务类型为恒定比特流CBR。

[1]给[2]发,发包间隔为0、01s,发包大小为512bytes;[3]给[4]发,发包间隔为0、01s,发包大小为512bytes。

二、实验结果:Node: 1, Layer:AppCbrClient,(0)Server address:2Node:1,Layer: AppCbrClient,(0)Firstpacket sent a t[s]:0、000000000Node: 1,Layer:AppCbrClient,(0)Lastpacket sent at [s]:99、990000000Node:1,Layer:AppCbrClient,(0) Session status:Not closedNode:1, Layer: AppCbrClient,(0)Totalnumber of bytess ent: 5120000Node: 1,Layer:AppCbrClient,(0) Total number of packets se nt: 10000Node:1, Layer: AppCbrClient,(0) Throughput (bits per second):409600Node:2, Layer:AppCbrServer, (0)Clientaddress: 1Node: 2, Layer:AppCbrServer,(0) Firstpacket received at [s]:0、007438001Node:2, Layer:AppCbrServer,(0)Last packetreceiveda t[s]:99、999922073Node:2,Layer:AppCbrServer,(0)Averageend—to-end delay[s]:0、739902205Node:2,Layer:AppCbrServer, (0)Session status:Notclose dNode:2, Layer:AppCbrServer,(0)Total number of bytes rec eived: 4975616Node:2, Layer:AppCbrServer,(0)Total numberof packetsreceived: 9718Node:2,Layer: AppCbrServer,(0) Throughput(bits per sec ond):398078Node:3,Layer:AppCbrClient, (0) Serveraddress:4Node:3, Layer: AppCbrClient,(0) First packet sentat [s]:0、000000000Node:3,Layer:AppCbrClient,(0) Last packet sentat [s]:99、990000000Node:3,Layer: AppCbrClient, (0) Session status:Not closedNode:3,Layer: AppCbrClient,(0)Total numberofbyt es sent:5120000Node: 3,Layer:AppCbrClient, (0) Totalnumber of packets sent:10000Node: 3,Layer:AppCbrClient,(0)Throughput(bit sper second):409600Node:4,Layer:AppCbrServer,(0) Client address:3Node:4,Layer:AppCbrServer,(0)First packetreceiveda t[s]: 0、003058001Node: 4, Layer: AppCbrServer,(0) Last packetreceived at [s]: 99、993058001Node:4,Layer:AppCbrServer, (0) Averageend-to-end delay[s]:0、003119031Node:4,Layer:AppCbrServer, (0) Sessionstatus:Not clos edNode:4, Layer:AppCbrServer,(0)Total number ofbyte sreceived: 5120000Node:4,Layer:AppCbrServer, (0)Total number ofpackets received:10000Node:4,Layer: AppCbrServer,(0)Throughput (bitspersecond): 409612通过仿真结果可以瞧出,节点[2]无法收到数据。

由于节点[3]就是节点[1]得一个隐终端,节点[1]无法通过物理载波检测侦听到节点[3]得发送,且节点[3]在节点[2]得传输范围外,节点[3]无法通过虚拟载波检测延迟发送,所以在节点[1]传输数据得过程中,节点[3]完成退避发送时将引起冲突。

三、课后思考1、RTS/CTS能完全解决隐终端问题吗?如果不能,请说明理由。

答:能。

对于隐发送终端问题,[2]与[3]使用控制报文进行握手(RTS—CTS),听到回应握手信号得[3]知道自己就是隐终端,便能延迟发送;对于隐接受终端问题,在多信道得情况下,[3]给[4]回送CTS告诉[4]它就是隐终端,现在不能发送报文,以避免[4]收不到[3]得应答而超时重发浪费带宽。

2、如何设计仿真场景来验证暴露终端问题?答:只需更改业务流配置:业务类型为恒定比特流CBR.[2]给[1]发,发包间隔为0、01s,发包大小为512bytes;[3]给[4]发,发包间隔为0、01s,发包大小为512bytes。

观察在[2]给[1]发送数据得同时,[3]给[4] 发送数据会不会被影响。

3、如何设计协议使暴露终端场景下得流实现并发?答:至少要使用两个信道资源,在数据信道上进行RTS-CTS握手,在数据信道上发送数据报文。

在[2]给[1]发送数据报文时,[3]也想向[4]发送数据报文,通过控制信道向[4]发送RTS,[4]也从控制信道向[3]回送CTS,这样[3]就不会因为[2]得数据信号与[4]得回应信号产生碰撞而听不到[4]得回应了.这样就可以实现并发了。

实验二无线局域网DCF协议饱与吞吐量验证一、实验设定基本参数配置:仿真时长100S随机数种子1仿真区域150x150节点数100。

业务流配置:业务类型为CBR,发包大小为512bytes,发包间隔为0、01S,分别测出5、10、15 、20 、25、30、35、40、45 、50 条流得吞吐量。

二、实验结果:5条:Node:1, Layer: AppCbrClient, (4)Serveraddress:55Node:1,Layer: AppCbrClient,(4)Firstpacket sentat [s]:0、000000000Node: 1,Layer:AppCbrClient, (4)Lastpacket sent at [s]:99、990000000Node:1,Layer: AppCbrClient, (4)Sessionstatus:Not closedNode:1,Layer:AppCbrClient,(4)Totalnumber of bytes sent:5120000Node:1,Layer:AppCbrClient,(4)Totalnumberof packets sent: 10000Node:1,Layer:AppCbrClient,(4)Throughput (bits per second):409600Node:1,Layer:AppCbrClient, (3)Server address:54Node:1, Layer:AppCbrClient, (3)First packet sentat[s]:0、000000000Node:1,Layer: AppCbrClient,(3)Last packetsent at[s]: 99、990000000Node:1,Layer:AppCbrClient,(3)Session status:Not closedNode: 1, Layer:AppCbrClient,(3)Total number of bytes sen t: 5120000Node:1,Layer:AppCbrClient,(3)Totalnumber of pack etssent:10000Node:1, Layer:AppCbrClient,(3)Throughput(bitsper se cond):409600Node:1, Layer:AppCbrClient,(2)Server address:53Node:1,Layer:AppCbrClient,(2) Firstpacket sent at[s]: 0、000000000Node:1,Layer: AppCbrClient, (2)Lastpacketsent at[s]: 99、990000000Node:1,Layer:AppCbrClient, (2) Session status: Not closedNode:1, Layer:AppCbrClient,(2) Total number of bytes sent: 5120000Node: 1, Layer:AppCbrClient,(2) Total number of packetssent:10000Node:1,Layer:AppCbrClient, (2) Throughput (bitsper second):409600Node:1,Layer: AppCbrClient, (1) Serveraddress: 52Node:1, Layer:AppCbrClient, (1)First packetsentat[s]: 0、000000000Node:1,Layer:AppCbrClient,(1) Last packetsentat[s]:99、990000000Node: 1,Layer: AppCbrClient,(1) Session status: Not closedNode:1,Layer:AppCbrClient,(1)Totalnumber of bytes sent:5120000Node:1,Layer:AppCbrClient, (1) Total number ofpackets sent:10000Node:1,Layer: AppCbrClient, (1) Throughput (bits persecond):409600Node:1,Layer:AppCbrClient,(0) Server address: 51Node: 1, Layer:AppCbrClient, (0)Firstpacket sent at [s]: 0、000000000Node:1,Layer:AppCbrClient, (0) Last packet sent at[s]:99、990000000Node:1,Layer:AppCbrClient,(0) Sessionstatus: Not cl osedNode:1,Layer: AppCbrClient,(0) Total number of bytessent: 5120000Node:1,Layer:AppCbrClient,(0) Total numberof packets sent:10000Node:1, Layer:AppCbrClient,(0)Throughput (bits per seco nd):409600Node:51,Layer:AppCbrServer,(0) Client address:1Node: 51,Layer:AppCbrServer, (0)Firstpacket receivedat [s]:0、003056858Node:51,Layer: AppCbrServer,(0)Last packet received at [s]:99、995493030Node:51, Layer: AppCbrServer,(0)Average end-to-end delay [s]: 0、351972641Node: 51,Layer:AppCbrServer, (0)Session status:NotclosedNode:51,Layer:AppCbrServer,(0) Total number ofbytes received:5102592Node: 51,Layer:AppCbrServer,(0) Total number of packetsrecei ved: 9966Node:51,Layer:AppCbrServer,(0)Throughput(bits per second): 408219Node: 52, Layer: AppCbrServer,(1)Client address: 1Node: 52, Layer:AppCbrServer,(1)First packetreceived at [s]:0、006449537Node:52,Layer:AppCbrServer,(1) Lastpacket received at [s]: 99、998965709Node: 52, Layer:AppCbrServer,(1)Averageend-to-end delay [s]:0、355584451Node: 52,Layer: AppCbrServer, (1) Sessionstatus:Not c losedNode: 52, Layer:AppCbrServer, (1)Total number of bytes received:5102592Node:52,Layer: AppCbrServer, (1)Total number of packets received:9966Node: 52,Layer:AppCbrServer, (1)Throughput (bits per second): 408233Node: 53, Layer: AppCbrServer,(2) Client address:1Node: 53,Layer:AppCbrServer,(2)First packet receiveda t[s]: 0、010001809Node: 53,Layer:AppCbrServer,(2) Lastpacket received at[s]:99、992000125Node:53,Layer:AppCbrServer, (2) Averageend—to—end delay [s]:0、358534977Node:53, Layer: AppCbrServer,(2)Session status:Not closedNode: 53,Layer:AppCbrServer,(2)Totalnumberofbytes received:3926016Node: 53, Layer: AppCbrServer,(2) Total numberof packets received:7668Node:53,Layer:AppCbrServer,(2)Throughput (bits per sec ond):314112Node:54,Layer: AppCbrServer,(3)Client address: 1Node:54,Layer:AppCbrServer,(3)Firstpacket receivedat [s]:0、013774900Node: 54,Layer:AppCbrServer,(3) Last packetreceived at [s]: 0、773715844Node:54, Layer:AppCbrServer, (3) Average end—to—enddelay[s]: 0、184107930Node: 54, Layer:AppCbrServer, (3)Session status:NotclosedNode:54,Layer:AppCbrServer,(3)Total numberof bytes rec eived:22016Node:54,Layer:AppCbrServer, (3)Total number of packetsreceived:43Node:54,Layer: AppCbrServer,(3)Throughput (bits persecond):1761Node:55, Layer:AppCbrServer,(4)Client address: 1Node:55,Layer:AppCbrServer,(4) First packet received at [s]:0、017127686Node: 55,Layer:AppCbrServer,(4)Lastpacket received at [s]:0、777148630Node: 55,Layer:AppCbrServer, (4)Averageend—to—end delay [s]:0、187729553Node:55, Layer:AppCbrServer,(4)Session status:Not closedNode:55, Layer: AppCbrServer,(4)Total number of bytesre ceived: 22016Node:55,Layer: AppCbrServer,(4)Totalnumber of packets received:43Node:55,Layer:AppCbrServer,(4)Throughput(bitspersecond): 176110、15、20、25、30、35、40、45、50条省略各发送节点发包间隔较大,当网络中发送节点较少时,网络还未饱与。

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