Question

使用NS2和NAM，我想显示包含许多节点的树形拓扑。如何设置图像中显示的节点和方向的位置。第一张图像显示在编辑和更改NAM工具中的节点位置之前。使用NAM工具手动编辑节点位置后显示第二个图像。我想看到第二个图像中显示的节点位置。我不想手动编辑。如何为此编写TCL代码？

以下是TCL代码

    #Create a simulator object
    set ns [new Simulator]
    $ns color 1 Green
    $ns color 2 Red
    $ns color 3 blue
    $ns color 4 magenta
    #Tell the simulator to use dynamic routing
    $ns rtproto DV
    set tracefile [open out.tr w]
    $ns trace-all $tracefile
    #Open the nam trace file
    set nf [open out.nam w]
    $ns namtrace-all $nf
    #Define a 'finish' procedure
    proc finish {} {
            global ns tracefile nf
            $ns flush-trace
        #Close the trace file
            close $nf 
        #Execute nam on the trace file
            exec nam out.nam &
            exit 0
    }
    #Create thirty six nodes
    for {set i 0} {$i < 21} {incr i} {
            set n($i) [$ns node]
    }
    $ns duplex-link $n(0) $n(1) 1Mb 10ms DropTail 
    $ns duplex-link $n(0) $n(2) 1Mb 10ms DropTail 
    $ns duplex-link $n(0) $n(3) 1Mb 10ms DropTail 
    $ns duplex-link $n(0) $n(4) 1Mb 10ms DropTail 
    $ns duplex-link $n(1) $n(5) 1Mb 10ms DropTail 
    $ns duplex-link $n(1) $n(7) 1Mb 10ms DropTail 
    $ns duplex-link $n(1) $n(9) 1Mb 10ms DropTail 
    $ns duplex-link $n(1) $n(11) 1Mb 10ms DropTail
    $ns duplex-link $n(2) $n(5) 1Mb 10ms DropTail 
    $ns duplex-link $n(2) $n(7) 1Mb 10ms DropTail 
    $ns duplex-link $n(2) $n(9) 1Mb 10ms DropTail 
    $ns duplex-link $n(2) $n(11) 1Mb 10ms DropTail
    $ns duplex-link $n(3) $n(6) 1Mb 10ms DropTail 
    $ns duplex-link $n(3) $n(8) 1Mb 10ms DropTail 
    $ns duplex-link $n(3) $n(10) 1Mb 10ms DropTail
    $ns duplex-link $n(3) $n(12) 1Mb 10ms DropTail
    $ns duplex-link $n(4) $n(6) 1Mb 10ms DropTail 
    $ns duplex-link $n(4) $n(8) 1Mb 10ms DropTail 
    $ns duplex-link $n(4) $n(10) 1Mb 10ms DropTail
    $ns duplex-link $n(4) $n(12) 1Mb 10ms DropTail
    $ns duplex-link $n(5) $n(13) 1Mb 10ms DropTail
    $ns duplex-link $n(5) $n(14) 1Mb 10ms DropTail
    $ns duplex-link $n(6) $n(13) 1Mb 10ms DropTail
    $ns duplex-link $n(6) $n(14) 1Mb 10ms DropTail
    $ns duplex-link $n(7) $n(15) 1Mb 10ms DropTail
    $ns duplex-link $n(7) $n(16) 1Mb 10ms DropTail
    $ns duplex-link $n(8) $n(15) 1Mb 10ms DropTail
    $ns duplex-link $n(8) $n(16) 1Mb 10ms DropTail
    $ns duplex-link $n(9) $n(17) 1Mb 10ms DropTail
    $ns duplex-link $n(9) $n(18) 1Mb 10ms DropTail
    $ns duplex-link $n(10) $n(17) 1Mb 10ms DropTail
    $ns duplex-link $n(10) $n(18) 1Mb 10ms DropTail
    $ns duplex-link $n(11) $n(19) 1Mb 10ms DropTail
    $ns duplex-link $n(11) $n(20) 1Mb 10ms DropTail
    $ns duplex-link $n(12) $n(19) 1Mb 10ms DropTail
    $ns duplex-link $n(12) $n(20) 1Mb 10ms DropTail
    # Provide initial location of mobilenodes
    $n(0) set X_ 0.0
    $n(0) set Y_ 0.0
    #Create a UDP Source Node
    set udp0 [new Agent/UDP]
    $udp0 set class_ 1
    $ns attach-agent $n(0) $udp0
    #Create a UDP1 Source Node
    set udp1 [new Agent/UDP]
    $udp1 set class_ 2
    $ns attach-agent $n(0) $udp1 
    set cbr0 [new Application/Traffic/CBR]
    $cbr0 set packetSize_ 250
    $cbr0 set interval_ 0.010
    $cbr0 attach-agent $udp0
    set cbr1 [new Application/Traffic/CBR]
    $cbr1 set packetSize_ 250
    $cbr1 set interval_ 0.010
    $cbr1 attach-agent $udp1
    set null0 [new Agent/Null]
    $ns attach-agent $n(13) $null0
    set null1 [new Agent/Null]
    $ns attach-agent $n(20) $null1
    $ns connect $udp0 $null0
    $ns connect $udp1 $null1
    $ns at 0.0 "$cbr0 start"
    $ns at 0.0 "$cbr1 start"
    $ns at 5.0 "finish"
    #Run the simulation
    $ns run

Answer 1

这都是传播节点的问题。有几种方法可以做到，但关键是你有一个矩形空间。

# Describe the indices of the nodes and how we approximately want to arrange them.
set indexLayout {
    {0}
    {1 2 3 4}
    {5 6 7 8 9 10 11 12}
    {13 14 15 16 17 18 19 20}
}

# Describe the space we're going to lay them out over; you might need to tune this
set originX 0
set originY 0
set width   100
set height  100

# Do the layout
set nRows [llength $indexLayout]
set rowsize [expr {$height / $nRows}]
set rowY [expr {$originY + $rowsize / 2}]
foreach row $indexLayout {
    set nCols [llength $row]
    set colsize [expr {$width / $nCols}]
    set rowX [expr {$originX + $colsize / 2}]
    foreach index $row {
        $n($index) set X_ $rowX
        $n($index) set Y_ $rowY
        set rowX [expr {$rowX + $colsize}]
    }
    set rowY [expr {$rowY + $rowsize}]
}

如果您将节点放在外，我不确定是否需要显式设置链接方向，但如果这样做，您应该阅读此Stack Overflow问题：Angle based orientation ns2 not working以获取有关语法的信息。如果你需要明确地放置链接，你需要做一些几何（虽然我不明白为什么有人会默认需要它）。

Answer 2

示例网格：pbcast_sim.tcl + p_bcast.tcl http://disc.ece.illinois.edu/downloads/lab108.html →→http://disc.ece.illinois.edu/downloads/pbcast_sim.tcl 和http://disc.ece.illinois.edu/downloads/p_bcast.tcl

模拟示例：$ ns pbcast_sim.tcl -prob 20

如何使用TCL代码设置NAM中显示的节点的位置和方向？

2 个答案: