标签：des style http color io os ar for strong
这个网站上的一系列讲解NS2的内容真的是深入浅出，看完立刻豁然开朗。所以就接连转了几篇。
Scheduling Events那篇里的例子特别好，看完就懂了。
http://www.mathcs.emory.edu/~cheung/Courses/558-old/Syllabus/90-NS/
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A Agent/TCP/Reno or Agent/TCP/Tahoe needs to be attached to some Node (see figure)
Also, a Agent/TCP/Reno or Agent/TCP/Tahoe need to be associated with a Agent/TCP/Sink !
A Agent/TCP/Sink sends ACK packets and needs to be attached to some Node (see figure)
A Application/FTP needs to be attached to some TCP agent (see figure)
The Application/FTP does not need to be asscoiated with a receiver:
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The Simulator object is the network simulation system and provides many methods needed to construct the network simulation.
new Simulator |
set ns [new Simulator] |
You only need one Simulator object
If you look in the source of a NS script, you will always see this statement at the top of the program !
The following expression will return a Node object in NS that you use to simulate ONE router:
set ns [new Simulator] [$ns node] |
set ns [new Simulator] set n0 [$ns node] |
Example: create Nodes n(0), n(1), ..., n(9):
for {set i 0} {$i < 10} {incr i} {
set n($i) [$ns node]
}
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BTW, a duplex link is actually 2 simplex links..
Units: b (#bits/sec), Mb (#Megabits/sec)
Units: s (seconds), ms (milliseconds)
Some commonly used values:
We will mostly use DropTail
set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1 10Mb 10ms DropTail
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For example, the bottleneck link is f times the normal bandwidth in other network links
set bw 10 set f 0.5 $ns duplex-link $n0 $n1 [expr $bw]Mb 10ms DropTail $ns duplex-link $n0 $n1 [expr $f*$bw]Mb 10ms DropTail |
$ns duplex-link $n0 $n1 10Mb 10ms DropTail $ns queue-limit $n0 $n1 10 |
Queue/DropTail set queue-limit $n0 $n1 10
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Example:
set tcp1 [new Agent/TCP/Reno]
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Example:
set sink1 [new Agent/TCPSink]
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They can be attached to any Node object
$ns attach-agent NODE TCP-Agent
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set ns [new Simulator] set node1 [$ns node] set tcp1 [new Agent/TCP/Reno] $ns attach-agent $node1 $tcp1 |
We need to tell NS the destination of each sending Transport Agent.
The destination must be a receiving Transport Agent.
set ns [new Simulator] set tcp1 [new Agent/TCP/Reno] set sink1 [new Agent/TCPSink] (tcp1 and sink1 must also be attached to nodes, this step is omitted) $ns connect $tcp1 $sink1 |
This will make NS route all packets from the source tcp1 towards the destination sink1
set tcp1 [new Agent/TCP/Reno]
$tcp1 set packetSize_ 552
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Example:
set tcp1 [new Agent/TCP/Reno]
set pksize [$tcp1 set packetSize_] // get packetzise used
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new Application/FTP |
set ftp1 [new Application/FTP]
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set tcp1 [new Agent/TCP/Reno]
set ftp1 [new Application/FTP]
$ftp1 attach-agent $tcp1
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set ftp1 [new Application/FTP]
$ftp1 start // Start the FTP application
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set ftp1 [new Application/FTP]
$ftp1 stop // Stop the FTP application
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When the FTP traffic generator stops generating traffic, TCP will have no data to send and will "go quiet".
You can start the FTP again after stopping it.
http://www.mathcs.emory.edu/~cheung/Courses/558-old/Syllabus/90-NS/2-NS-Prog/ns.html#links
标签：des style http color io os ar for strong
原文地址：http://www.cnblogs.com/forcheryl/p/4053016.html
