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Multicast in ns-2

報告者 :陳沐恩

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Multicast 簡介

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Multicast Routing

set ns [new Simulator]

$ns multicast

Or

set ns [new Simulator –multicast on]

set mproto <type>

<type>:CtrMcast, DM, ST, BST

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Multicast Routing

all nodes will contain multicast protocol agents set mrthandle [$ns mrtproto $mproto]

allocating a multicast address set group [Node allocaddr]

define an agent and as a multicast source for the group $udp1 set dst_addr_ $group $udp1 set dst_port_ 0

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Multicast Routing

create a receiver agent set rcvr [new Agent/LossMonitor]

specify which nodes join the group and when they want to join the group $ns at 0.0 "$n1 join-group $rcvr $group"

make a node leave the group at a time $ns at 1.6 "$n2 leave-group $rcvr $group"

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Multicast:Step1

Scheduler , tracing , and topology# Create scheduler

set ns [new Simulator]

# Turn on multicast

$ns multicast

# Turn on Tracing

set fd [new “mcast.nam” w]

$ns namtrace-all $fd

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Multicast:Step2

Topology# Create nodesset n0 [$ns node]set n1 [$ns node]set n2 [$ns node]set n3 [$ns node]# Create links$ns duplex-link $n0 $n1 1.5Mb 10ms DropTail$ns duplex-link $n0 $n2 1.5Mb 10ms DropTail$ns duplex-link $n0 $n3 1.5Mb 10ms DropTail

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Multicast:Step3

Routing and group setup# Routing protocol: let’s run distance vector

set mproto DM

# Allocate group addresses

set group1 [Node allocaddr]

set group2 [Node allocaddr]

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Multicast:Step4

Sender0# Transport agent for the traffic sourceset udp0 [new Agent/UDP]$ns attach-agent $n1 $udp0$udp0 set dst_addr_ $group1$udp0 set dst_port_ 0# Constant Bit Rate source #0set cbr0 [new Application/Traffic/CBR]$cbr0 attach-agent $udp0# Start at time 1.0 second$ns at 1.0 "$cbr0 start"

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Multicast:Step5

Sender1# Transport agent for the traffic sourceset udp1 [new Agent/UDP]$ns attach-agent $n3 $udp1$udp1 set dst_addr_ $group2$udp1 set dst_port_ 0# Constant Bit Rate source #0set cbr1 [new Application/Traffic/CBR]$cbr1 attach-agent $udp1# Start at time 1.1 second$ns at 1.1 "$cbr1 start"

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Multicast:Step6

Receiver with dynamic membership# Can also be Agent/Null

set rcvr [new Agent/LossMonitor]

# Assign it to node $n2

$ns at 1.2 "$n2 join-group $rcvr $group2"

$ns at 1.25 "$n2 leave-group $rcvr $group2"

$ns at 1.3 "$n2 join-group $rcvr $group2"

$ns at 1.35 "$n2 join-group $rcvr $group1"

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Multicast:Step7

End-of-simulation wrapper (as usual)$ns at 2.0 "finish"proc finish {} {global ns fdclose $fd$ns flush-traceputs "running nam..."exec nam out.nam &exit 0}$ns run

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抽考題目使用 DM這個multicast protocol，讓所有

node包含multicast protocol agent，並建立一個multicast 的 group，定義一個 udp 的agent 給 group當作multicast的來源端。

提供 tcl，請依要求補上缺少的 code(5 行 )