NS2学习笔记（一）

 1 set ns [new Simulator]#建立一个新的模拟对象simulator
 2 
 3 set tracef [open example1.tr w]#变量tracef指向example1.tr文件
 4 #ns trace-all $tacef#记录模拟过程trace数据
 5 set namtf [open example1.nam w]#变量namtf指向example1.nam文件
 6 $ns namtrace-all $namtf#记录nam的trace数据
 7 
 8 proc finish {} {关闭两个trace文件，在模拟结束后调用nam程序
 9     global ns tracef namtf
10     $ns flush-trace
11     close $tracef
12     close $namtf
13     exec nam example1.nam &
14     exit 0
15 )
16 
17 set n0 [$ns node]#创建节点n0
18 set n1 [$ns node]#创建节点n1
19 
20 $ns duplex-link $n0 $n1 1Mb 10ms DropTail#在n0和n1之间建立一条双向的链路，带宽1Mbit/s，时延10ms，队列类型为DropTail。
21 
22 set udp0 [new Agent/UDP]#创建一个udp0 Agent
23 $ns attach-agent $no $udp0#将udp0绑定到n0上
24 
25 set cbr0 [new Application/Traffic/CBR]#创建一个CBR流量发生器
26 $cbr0 set packetSize_ 500#分组大小为500B
27 $cbr0 set interval_ 0.005#发送间隔为5ms
28 $cbr0 attach-agent $udp0#将CBR绑定到udp0上
29 
30 set null0 [new Agent/Null]#创建一个Null Agent作为数据接收器
31 $ns attach-agent $n1 $null0#绑定到n1上
32 
33 $ns connect $udp0 $null0#将两个Agent连接起来
34 
35 $ns at 0.5 "$cbr0 start"#0.5s时启动cbr0
36 $ns at 4.5 "$cbr0 stop"#4.5s时停止cbr0
37 
38 $ns at 5.0 "finish"#5.0s时调用finish过程
39 $ns run#开始模拟

 1 set val(chan) Channel/WirelessChannel #channel type，val(chan)作为变量名是一个整体，下同
 2 set val(proc) Propagation/TwoRayGround #radio-propagation model
 3 set val(netif) Phy/WirelessPhy #network interface type
 4 set val(mac) Mac/802_11 #MAC type
 5 set val(ifq) Queue/DropTail/PriQueue #interface queue type
 6 set val(ll) LL #link layer type
 7 set val(ant) Antenna/OmniAntenna #antenna model
 8 set val(ifqlen) 50 #max packet in ifq
 9 set val(nn) 2 #number of mobilenodes
10 set val(rp) AODV #routing protocol
11 set val(x) 500 #X dimension of the topography
12 set val(y) 500 #Y dimension of the topography
13 
14 set ns [new Simulator]
15 
16 set tracefd [open wireless.tr w]
17 $ns trace-all $tracefd
18 set namtracefd [new wireless.nam w]
19 $ns namtrace-all-wireless $namtracefd $val(x) $val(y)
20 
21 set topo [new Topography]#建立一个Topography对象，该对象可以保证节点在拓扑边界范围内运动
22 $topo load_flatgrid $val(x) $val(y)#设定模拟所用场景的大小
23 
24 create-god $val(nn) #建立一个God对象，主要用来对路由协议做性能评价；节点的MAC对象会调用God对象，因此即使我们在这里并不适用God对象，仍然需要建立一个God对象
25 
26 $ns node-config -adhocRouting $val(rp)\ #配置节点参数
27     -llType $val(ll)28     -macType $val(mac)29     -ifqType $val(ifq)30     -ifqLen $val(ifqlen)31     -antType $val(ant)32     -propType $val(prop)33     -phyType $val(netif)34     -channelType $val(chan)35     -topoInstance $topo36     -agentTrace ON37     -routerTrace ON38     -macTrace OFF39     -movementTrace OFF
40 
41 for{set i 0} {$i < $val(nn)} {incr i} {
42     set node_($i) [$ns node]
43     $node_($i) random-motion 0 #disable random motion 禁止节点随机移动，让节点按脚本规定的方式移动
44 
45 $node_(0) set X_ 5.0 #设定节点初始坐标X,Y,Z
46 $node_(0) set Y_ 2.0
47 $node_(0) set Z_ 0.0
48 
49 $node_(1) set X_ 390.0
50 $node_(1) set Y_ 385.0
51 $node_(1) set Z_ 0.0
52 
53 $ns at 5.0 "$node_(1) setdest 25.0 20.0 15.0"#节点1在5s时以15m/s的速度向坐标(25.0,20.0)的点运动
54 $ns at 1.0 "$node_(0) setdest 20.0 18.0 1.0"
55 
56 $ns at 10 "$node_(1) setdest 490.0 480.0 15.0"
57 
58 set tcp [new Agent/TCP]
59 $tcp set class_ 2
60 set sink [new Agent/TCPSink]
61 $ns attach-agent $node_(0) $tcp
62 $ns attach-agent $node_(1) $sink
63 $ns connect $tcp $sink
64 set ftp [new Appication/FTP]
65 $ftp attach-agent $tcp
66 
67 $ns at 1.0 "$ftp start"
68 for {set i 0} {$i < $val(nn)} {incr i} {
69     $ns at 15.0 "$node_($i) reset"
70 }
71 $ns at 15.0 "stop"
72 
73 proc stop{} {
74     global ns tracefd nametracefd
75     $ns flush-trace
76     close $tracefd
77     close $nametracefd
78     exec nam wireless nam &
79     exit 0
80 }
81 
82 $ns run