##################################################################### setup UDP connectionsset udp1 [new Agent/UDP]$udp1 set fid_ 2222set lm [new Agent/LossMonitor]$ns_ attach-agent $node_(0) $udp1$ns_ attach-agent $node_(1) $lm$ns_ connect $udp1 $lm# Mandatory$node_(0) 2222 ftp rate_ $opt(rate)set cbr1 [new Application/Traffic/CBR]$cbr1 set rate_ $opt(rate)$cbr1 attach-agent $udp1$ns_ color 2222 blue$ns_ at $opt(start) "$cbr1 start"#$ns_ at 1.5 "$ns_ detach-agent $node_(0) $udp1"