为 NS2 上给定的任意数量的节点创建随机有线拓扑

Question

我想使用 NS2 创建和模拟有线拓扑。尝试编写一个 tcl 并使用 rand() 定位节点和链接。我的解决方案是：

### Create a simulator object
set ns [new Simulator]
set num_node 10
set num_flow 5
set x_dim 150
set y_dim 150

### Define different colors for data flows (for NAM)
$ns color 1 Blue
$ns color 2 Red

### Open the NAM trace file
set nf [open out.nam w]
$ns namtrace-all $nf
set tracefd [open out.tr w]
$ns trace-all $tracefd

### set up topography object
set topo [new Topography];            # This is needed for wireless
$topo load_flatgrid $x_dim $y_dim;    # Setting a 2D space for the nodes

### Define a 'finish' procedure
proc finish {} {
    global ns nf tracefd
    $ns flush-trace
    ### Close the NAM trace file
    close $nf
    close $tracefd
    ### Execute NAM on the trace file
    exec nam out.nam &
    exit 0
}

#Create four nodes
for {set i 0} {$i < [expr $num_node]} {incr i} {
    set n($i) [$ns node]
    puts "Created node $i"
}

### Create links between the nodes
for {set i 0} {$i < [expr $num_node + 1]} {incr i} {
    set s_node [expr int($num_node*rand())];     # src node
    set d_node $s_node
    while {$d_node==$s_node} { ;                 # while the random pair are same node
        set d_node [expr int($num_node*rand())]; # dest node
    }
    $ns duplex-link $n($s_node) $n($d_node) 2Mb 10ms DropTail
    $ns queue-limit $n($s_node) $n($d_node) 50
    puts "Linking $s_node and $d_node"
}

### Give node position (for NAM)
set i 0
while {$i < $num_node } {
    ### Set random position for nodes
    set x_pos [expr int($x_dim*rand())];   # random settings
    set y_pos [expr int($y_dim*rand())];   # random settings

    $n($i) set X_ $x_pos
    $n($i) set Y_ $y_pos
    $n($i) set Z_ 0.0
    puts "Put $i to ($x_pos , $y_pos)"

    #puts -nonewline $topofile "$i x: [$node_($i) set X_] y: [$node_($i) set Y_] \n"
    incr i;
}; 

### Setup UDP connections
for {set i 0} {$i < [expr $num_flow]} {incr i} {
    set s_node [expr int($num_node*rand())];     # src node
    set d_node $s_node
    while {$d_node==$s_node} {;                  # while the random pair are same node
        set d_node [expr int($num_node*rand())]; # dest node
    }
    set udp($i) [new Agent/UDP]
    $udp($i) set class_ $i
    $ns attach-agent $n($s_node) $udp($i)
    set null($i) [new Agent/Null]
    $ns attach-agent $n($d_node) $null($i)
    $ns connect $udp($i) $null($i)
    $udp($i) set fid_ $i
    puts "Flow $s_node - $d_node"
}

### Setup a CBR over UDP connections
for {set i 0} {$i < [expr $num_flow]} {incr i} {
    set cbr($i) [new Application/Traffic/CBR]
    $cbr($i) attach-agent $udp($i)
    $cbr($i) set type_ CBR
    $cbr($i) set packet_size_ 1000
    $cbr($i) set rate_ 1mb
    $cbr($i) set random_ false
    puts "setting cbr for $i"
}

### Schedule events for the CBR and FTP agents
for {set i 0} {$i < [expr $num_flow]} {incr i} {
    $ns at 0.1 "$cbr($i) start"
}

for {set i 0} {$i < [expr $num_flow]} {incr i} {
    $ns at 4.5 "$cbr($i) stop"
}

for {set i 0} {$i < [expr $num_node]  } { incr i} {
    $ns initial_node_pos $n($i) 4
}

### Run the simulation
$ns run

但是随机化经常会产生错误的链接，从而在模拟中出现问题并出现此错误：

--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---
    _o28: no target for slot 4294967295
    _o28 type: Classifier/Hash/Dest
content dump:
classifier _o28
    0 offset
    0 shift
    1073741823 mask
    1 slots
        slot 5: _o268 (Classifier/Port)
    -1 default
---------- Finished standard no-slot{} default handler ----------

但这也是随机的，并不总是发生。当没有出现时，nam 文件显示存在节点的重复定义。有人可以给我一些关于如何创建具有随机有效链接的随机有线拓扑的指导吗？

Answer 1

你的文件 "random-wired.tcl" 在这里工作正常...... PCLinuxOS 2017.04 - x86_64.

$ ns235-64-orig random-wired.tcl
Created node 0
Created node 1
Created node 2
Created node 3
Created node 4
Created node 5
Created node 6
Created node 7
Created node 8
Created node 9
Linking 9 and 0
Linking 9 and 8
Linking 5 and 8
Linking 1 and 6
Linking 9 and 6
Linking 8 and 0
Linking 1 and 4
Linking 3 and 7
Linking 8 and 7
Linking 1 and 2
Linking 9 and 0
Put 0 to (139 , 71)
Put 1 to (107 , 146)
Put 2 to (14 , 9)
Put 3 to (16 , 23)
Put 4 to (89 , 30)
Put 5 to (26 , 65)
Put 6 to (46 , 76)
Put 7 to (87 , 31)
Put 8 to (12 , 105)
Put 9 to (89 , 56)
Flow 6 - 4
Flow 0 - 1
Flow 2 - 8
Flow 5 - 2
Flow 2 - 3
setting cbr for 0
setting cbr for 1
setting cbr for 2
setting cbr for 3
setting cbr for 4

已创建文件 out.nam 3.3MB，out.tr 1.4MB。和 nam：一些节点显示 activity。

--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---

... 是某些模拟/某些 Linux OS 的已知错误。另一个 ns2 友好 OS 是 CentOS 7 - 64bit ：你的文件运行正常。不太好的消息：Ubuntu 16.04 - 64 和 Ubuntu 17.04 - 64 失败。实际上 Ubuntu 不是 ns2 的首选。不是很 ns2 友好它的 "different" 修补例如。 libc6.

示例，rand()：aodv18.tcl、aodv_802_15_4.tcl、AODV-Jenova.tcl、aodv-Soumia.tcl , AODV-testcode-rand.tcl → https://drive.google.com/file/d/0B7S255p3kFXNMXRfTTlEcm5KUW8/view?usp=sharing

编辑，2017 年 5 月 26 日：

--- Classfier::no-slot{} default handler

我认为找到了解决方案 http://www.linuxquestions.org/questions/linux-software-2/ns2-2-35-antnet-4175532576/#14 (post #14 @newthink) → 添加 $ns multicast :

set ns [ new Simulator ]
$ns multicast

与有问题的 Antnet 模拟完美配合。

Answer 2

$ns multicast 有时对我不起作用。我发现这个 post 说当生成的图断开连接时会发生此错误。

所以我一直在检查图表永远不会断开连接，并且每个节点至少有一个 link。

#nodeFlag_ keeps of which nodes has at least one link
for {set i 0} {$i < $num_node} {incr i} {
        set nodeFlag_($i) 0
    }
    ### Create links between the nodes
    for {set i 0} {$i < [expr $num_node + 1]} {incr i} {
        set s_node [expr int($num_node*rand())];     # src node
        set d_node $s_node
        while {$d_node==$s_node} { ;                 # while the random pair are same node
            set d_node [expr int($num_node*rand())]; # dest node
        }
        $ns duplex-link $node_($s_node) $node_($d_node) 2Mb 10ms DropTail
        set nodeFlag_($s_node) 1
        set nodeFlag_($d_node) 1
        $ns queue-limit $node_($s_node) $node_($d_node) 50
        puts "Linking $s_node and $d_node"
    }
    for {set i 0} {$i < $num_node} {incr i} {
            #see here
            if {$nodeFlag_($i) == 0} {
            set random [expr int($num_node*rand())]
            $ns duplex-link $node_($i) $node_($random) 2Mb 10ms DropTail
            puts "left link $i and $random"
        }
        puts "$nodeFlag_($i)"
    }

希望对您有所帮助。

编辑：我错了。错误仍然出现在一些模拟中。

Answer 3

尽管您上次编辑确保每个节点至少有一个 link，但它并不能保证所有节点之间都有一个完全连接的图。换句话说，您可能最终仍会拥有多个无法从其他节点访问的孤立节点组。

为 NS2 上给定的任意数量的节点创建随机有线拓扑

Creating random wired topology for given arbitrary number of nodes on NS2

random

tcl

ns2