# Polly Huang 8-7-98

set ns [new Simulator]
$ns multicast

set f [open out.tr w]
$ns trace-all $f
$ns namtrace-all [open out.nam w]

$ns color 1 red
# prune/graft packets
$ns color 30 purple
$ns color 31 green

set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

# Use automatic layout 
$ns duplex-link $n0 $n1 1.5Mb 10ms DropTail
$ns duplex-link $n1 $n2 1.5Mb 10ms DropTail
$ns duplex-link $n1 $n3 1.5Mb 10ms DropTail

$ns duplex-link-op $n0 $n1 orient right
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n1 $n3 orient right-down
$ns duplex-link-op $n0 $n1 queuePos 0.5

set mrthandle [$ns mrtproto DM {}]

set group1 [Node allocaddr]
set cbr0 [new Application/Traffic/CBR]
set udp0 [new Agent/UDP]
$cbr0 attach-agent $udp0
$ns attach-agent $n1 $udp0
$udp0 set dst_addr_ $group1
$udp0 set dst_port_ 0

set group2 [Node allocaddr]
set cbr1 [new Application/Traffic/CBR]
set udp1 [new Agent/UDP]
$cbr1 attach-agent $udp1
$udp1 set dst_addr_ $group2
$udp1 set dst_port_ 0
$udp1 set class_ 1
$ns attach-agent $n3 $udp1

set rcvr [new Agent/LossMonitor]
#$ns attach-agent $n3 $rcvr
$ns at 1.2 "$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"

$ns at 1.0 "$cbr0 start"
$ns at 1.1 "$cbr1 start"

$ns at 2.0 "finish"

proc finish {} {
	global ns
	$ns flush-trace

	puts "running nam..."
	exec nam out.nam &
	exit 0
}

$ns run