Network Simulator2
OTCL Analysis
Outline
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Basic OTCL Introduction
Simple.tcl
Simple-wireless.tcl
Trace File Analysis
Reference
NS2
Topology
(Use OTCL)
Kernel
(Use C++)
Topology
OTCL
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set x 100
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set y 200
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# 透過 expr 將 $x $y 當成數字作數學運算, 並設定 z 變數為300
set a [set b 100]
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# 設定 y 變數，y 值為200
set z [expr $x+$y]
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# 設定 x 變數，x 值為100(注意這100是字串)
# 設定 a = b = 100
set array_(1) 21
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# 設定一個陣列叫 array_, 並把 array_(1) 的值設為27
OTCL
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if
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if { $k>4 } {
puts " k > 4 "
} else {
puts " k < = 4 "
}
while
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下面程式, 代表一個 while 如在 i 大於等於0的情況下, 則將 b 的值和
i 相加並再回傳給 b, 然後 i 再減 1.
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set b 0 set i 100 while {$i > = 0} {
set b [expr $b+$i] incr i -1
}
OTCL
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for
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for {set i 100} {$i > =0} {incr i -1} {
# for 迴圈內所要執行的程式碼
}
副程式
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# 定義一個叫做 show 的 procedure
proc show {} {
... # 副程式內容 ...
}
NAM
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Nam 是一個能將 NS2 模擬結果視覺化顯示出來的工具,
他能顯示封包的流向和 Drop 等資訊.
執行方式:
nam < trace-file >
NAM
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$node color red
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$node shape square (circle, square, and hexagon)
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# 設定 node 形狀(預設圓形)
$node label "Text“
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# 設定 node 顏色
# 設定 node 的標籤
$node label-color blue
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# 設定 node 標籤的顏色
NAM
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$ns duplex-link-op $n1 $n2 color green
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$ns duplex-link-op $n1 $n2 label "Text"
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# 設定 Link 顏色
# 設定 Link 的標籤
$ns duplex-link-op $n1 $n2 label-color blue
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# 設定 Link 標籤的顏色
Basic NS2語法
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set ns [new Simulator]
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set node_ [$ns node]
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目的在創造一個 NS2 模擬的物件, 只要的功能在
1. 初使化封包格式( packet format) 2. 創造一個Scheduler
建立一個名稱叫做 node_ 的 Node
# 建立30個Nodes for {set i 0} {$i < 30} {incr i} {
set n($i) [$ns node] }
$ns simplex-link < n0 > < n1 > < bandwidth > < delay > <
queue_type >
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建立一條 Node n0 到 n1 的一條實體連結, 並設定頻寬、delay 時間和 queue
的 type, queue 的 type 有 DropTail(a FIFO queue)、FQ、SFQ、DRR、RED、
CBQ、CBQ/WRR 等 type
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$ns duplex-link $n0 $n1 2Mb 20ms DropTail
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# 在 n0 及 n1 間建立一個頻寬為2Mb, DropTail Queue 的 Link
Basic NS2語法
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$ns duplex-link < n0 > < n1 > < bandwidth > < delay > <
queue_type >
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同上, 不過是建立一條 duplex link 的連線
$ns attache-agent < node > < agent >
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將一個 agent 結合到一個 node 上, agent 簡單來說也就表示一個 node 上所
用的 protocol, 而一開始建立一個 Node 預設的 agent 是 Null. 範例如下 :
#創造一個TCP的Agent
set tcp [new Agent/TCP]
#TCP agent 結合到 node(n0)
$ns attach-agent $n0 $tcp
#但就此範例光是 TCP 無法產生任何 Traffic, 所以通常我們都會再建
立一些Application 的 Protocol 於 TCP 上(如 FTP、Telnet)
set ftp [new Application/FTP] $ftp attach-agent $tcp
Basic NS2語法
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$ns connect < agent1 > < agent2 >
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$ns trace-all < tracefile >
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在兩個 agent 中建立一條 logical 的連結, 不同於 Simplex-link 等方式所
建立的實體連結, 如 agent1 和 agent2 之間可能相隔好幾個點
將 ns2 模擬的內容寫回到在 < tracefile > 檔案中. 範例如下 :
建議此指令最好放在程式的前面 (在建立 node 和 link 之前), 以免模擬結果無
法完整寫回檔案
set nf [open out.tr w]
$ns trace-all $nf
$ns namtrace-all < tracefile >
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同樣是將 ns2 模擬的內容寫回到在 < tracefile > 檔案中, 不過可以放在
nam 上去顯示模擬畫面, 格式也不太一樣
Basic NS2語法
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$ns at < time > < event >
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在特定的時間 < time > 讓這個事件 < event > 被執行. 範例如下 :
# 在4.5秒的時候執行 ftp
$ns at 4.5 "$ftp start"
# 在5秒時候執行我們自己所定義的 finish 函式
$ns at 5.0 "finish“
$ns run
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開始執行 scheduler
Basic範例
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Two nodes, one link
set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1 1Mb 10ms DropTail
Basic範例
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#Create a UDP agent and attach it to node n0
set udp0 [new Agent/UDP]
$ns attach-agent $n0 $udp0
# Create a CBR traffic source and attach it to udp0
set cbr0 [new Application/Traffic/CBR]
$cbr0 set packetSize_ 500
$cbr0 set interval_ 0.005
$cbr0 attach-agent $udp0
Basic範例
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#Create a Null agent (a traffic sink) and attach it to
node n1
set null0 [new Agent/Null]
$ns attach-agent $n1 $null0
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#Connect the traffic source with the traffic sink
$ns connect $udp0 $null0
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#Schedule events for the CBR agent
$ns at 0.5 "$cbr0 start"
$ns at 4.5 "$cbr0 stop"
Basic範例
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#Create links between the nodes
$ns duplex-link $n0 $n2 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
$ns duplex-link $n3 $n2 1Mb 10ms SFQ
SFQ (stochastic fair queueing)
$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n2 $n3 orient right
Basic範例
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#Define different colors for data flows
$ns color 1 Blue
$ns color 2 Red
$udp0 set class_ 1
$udp1 set class_ 2
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#Monitor the queue for the link between node 2
and node 3
$ns duplex-link-op $n2 $n3 queuePos 0.5
Basic範例
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#Connect the traffic sources with the traffic sink
$ns connect $udp0 $null0
$ns connect $udp1 $null0
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#Schedule events for the CBR agents
$ns at 0.5 "$cbr0 start"
$ns at 1.0 "$cbr1 start"
$ns at 4.0 "$cbr1 stop"
$ns at 4.5 "$cbr0 stop"
Simple.tcl
set ns [new Simulator]
Simulator Object
$ns color 0 blue
Packet color
$ns color 1 red
$ns color 2 white
set n0 [$ns node]
Create four nodes
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
Simple.tcl (con.)
set f [open out.tr w]
$ns trace-all $f
set nf [open out.nam w]
$ns namtrace-all $nf
Trace file name
NAM file name
Simple.tcl (con.)
$ns
$ns
$ns
$ns
$ns
$ns
$ns
duplex-link $n0 $n2 5Mb 2ms DropTail
duplex-link $n1 $n2 5Mb 2ms DropTail
duplex-link $n2 $n3 1.5Mb 10ms DropTail
duplex-link-op $n0 $n2 orient right-up
duplex-link-op $n1 $n2 orient right-down
duplex-link-op $n2 $n3 orient right
duplex-link-op $n2 $n3 queuePos 0.5
Create three links
Place links location
Simple.tcl (con.)
set udp0 [new Agent/UDP]
$ns attach-agent $n0 $udp0
set cbr0 [new Application/Traffic/CBR]
$cbr0 attach-agent $udp0
set udp1 [new Agent/UDP]
$ns attach-agent $n3 $udp1
$udp1 set class_ 1
set cbr1 [new Application/Traffic/CBR]
$cbr1 attach-agent $udp1
Create UDP traffic
and CBR source node
Create UDP traffic
and CBR source node
Simple.tcl (con.)
set null0 [new Agent/Null]
$ns attach-agent $n3 $null0
Create UDP traffic
sink node
set null1 [new Agent/Null]
$ns attach-agent $n1 $null1
Create UDP traffic
sink node
Simple.tcl (con.)
$ns connect $udp0 $null0
$ns connect $udp1 $null1
Connect source node
and sink node
Simple.tcl (con.)
$ns at 1.0 "$cbr0 start“
$ns at 1.1 "$cbr1 start"
Set time to forward
packet traffic
Simple.tcl (con.)
set tcp [new Agent/TCP]
$tcp set class_ 2
set sink [new Agent/TCPSink]
$ns attach-agent $n0 $tcp
$ns attach-agent $n3 $sink
$ns connect $tcp $sink
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ns at 1.2 "$ftp start"
Create TCP traffic and
FTP
Simple.tcl (con.)
$ns at 1.35 "$ns detach-agent $n0 $tcp ; $ns
detach-agent $n3 $sink“
puts [$cbr0 set packetSize_]
puts [$cbr0 set interval_]
$ns at 3.0 "finish"
Traffic End
Simple.tcl (con.)
proc finish {} {
global ns f nf
$ns flush-trace
close $f
close $nf
puts "running nam..."
exec nam out.nam &
exit 0
}
$ns run
Execute NS
Record traffic in file
Execute NAM
Simple-wireless.tcl
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C:\cygwin\home\smallfirefly\nsallinone-2.26\ns-2.26\tcl\ex
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Simple-wireless.tcl
Basic – create node
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Create Node
set $node [$ns node]
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Start-position
$node set X_ <x1>
$node set Y_ <y1>
$node set Z_ <z1>
Basic – node movement
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Future destinations
$ns_ at $time $node setdest <x2> <y2>
<speed>
Basic OTCL
set ns_ [new Simulator]
Simulator Object
set tracefd [open simple.tr w]
Trace file name
$ns_ trace-all $tracefd
set namtrace [open simple.nam w]
NAM file name
$ns_ namtrace-all-wireless $namtrace $val(x) $val(y)
Basic – creating wireless topology
set topo [new Topography]
$topo load_flatgrid $opt(x) $opt(y)
where opt(x) and opt(y) are the boundaries used in
simulation.
Number of node
create-god $val(nn)
Basic – node config
$ns_ node-config -adhocRouting DSDV or DSR or TORA or
AODV \
-topoInstance $topo \
Wired-cum-wireless
MobileIP
-addressType hierarchical \
-wiredRouting ON \
-mobileIP ON \
-llType LL \
-macType Mac/802_11 \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyType Phy/WirelessPhy \
-channelType Channel/WirelessChannel \
-ifqType Queue/DropTail/PriQueue \
-ifqLen <integer> \
Basic – node config (con.)
-agentTrace ON or OFF \
-routerTrace ON or OFF \
-macTrace ON or OFF \
-movementTrace ON or OFF
Simple-wireless.tcl (con.)
for {set i 0} {$i < $val(nn) } {incr i} {
set node_($i) [$ns_ node]
$node_($i) random-motion 0;# disable random
motion
}
$node_(0) set X_ 5.0
$node_(0) set Y_ 2.0
$node_(0) set Z_ 0.0
$node_(1) set X_ 390.0
$node_(1) set Y_ 385.0
$node_(1) set Z_ 0.0
Simple-wireless.tcl (con.)
#
# Now produce some simple node movements
# Node_(1) starts to move towards node_(0)
#
$ns_ at 50.0 "$node_(1) setdest 25.0 20.0 15.0"
$ns_ at 10.0 "$node_(0) setdest 20.0 18.0 1.0"
# Node_(1) then starts to move away from node_(0)
$ns_ at 100.0 "$node_(1) setdest 490.0 480.0 15.0"
Simple-wireless.tcl (con.)
# Setup traffic flow between nodes
# TCP connections between node_(0) and node_(1)
set tcp [new Agent/TCP]
$tcp set class_ 2
set sink [new Agent/TCPSink]
$ns_ attach-agent $node_(0) $tcp
$ns_ attach-agent $node_(1) $sink
$ns_ connect $tcp $sink
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ns_ at 10.0 "$ftp start"
Simple-wireless.tcl (con.)
#
# Tell nodes when the simulation ends
#
for {set i 0} {$i < $val(nn) } {incr i} {
$ns_ at 150.0 "$node_($i) reset";
}
$ns_ at 150.0 "stop"
$ns_ at 150.01 "puts \"NS EXITING...\" ; $ns_ halt"
Simple-wireless.tcl (con.)
proc stop {} {
global ns_ tracefd
$ns_ flush-trace
close $tracefd
}
puts "Starting Simulation..."
$ns_ run
Basic
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Create Node
for {set i 0} {$i < $val(nn)} {incr i} {
set node_($i) [$ns_ node]}
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Random initial node position
for {set i 0} {$i < $val(nn)} {incr i}{
$node_($i) set X_ [expr { $val(x)*rand() } ]
$node_($i) set Y_ [expr { $val(y)*rand() } ]
$node_($i) set Z_ 0.0
$node_($i) radius 500}
Only wireless node
Node
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Initial node size
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for {set i 0} {$i < $val(nn)} {incr i} {
$ns_ initial_node_pos $node_($i) 50;}
Link
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$ns duplex-link $n0 $n2 2Mb 10ms DropTail
$node_($i) radius 500
Trace File
Trace File
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1.代表事件的類別
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r：代表目的端收到 packet
+：代表 packet 放入 queue 中
-：代表 packet 從 queue 中取出
d：代表 queue 已經滿了，這個 packet 被
drop 掉
Trace File
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2.
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3.
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代表事件發生的時間
代表 packet 的 source node
4.
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代表 packet 的 destination node
Trace File
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5.
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6.
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代表 packet 的類別(TCP or CBR)
代表 packet 的大小 (encoded in IP header)
7.
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代表 packet 的 flags
Trace File
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8.
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9.
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代表 connection(flow) 的 id
代表 source address ( node.port )
10.
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代表 destinations address ( node.port )
Trace File
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11.
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代表 packet 的 sequence number
( network layer protocol's )
12.
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代表 packet 的 id ( unique )
Reference
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Cygwin
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Cygwin+NS2安裝
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http://www.sims.berkeley.edu/~christin/nscygwin.shtml
NS2基本語法教學(中文)
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http://cygwin.com/
http://netlab.cse.yzu.edu.tw/ns2/ns2_website/
華玄明
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http://ns2.mis.must.edu.tw/index.htm
Reference (con.)
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File download
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FTP
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140.136.206.252
Port:21
Name: ns2
Password: ns2123