#TCP Sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
set tcp_src($j) [new Agent/TCP/Reno]
} 

#TCP Destinations
for {set j 1} {$j<=$NumbSrc} { incr j } {
set tcp_snk($j) [new Agent/TCPSink]
}  

#Connections
for {set j 1} {$j<=$NumbSrc} { incr j } {
$ns attach-agent $S($j) $tcp_src($j)
$ns attach-agent $n3 $tcp_snk($j)
$ns connect $tcp_src($j) $tcp_snk($j)
}  

#FTP sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
set ftp($j) [$tcp_src($j) attach-source FTP]
}       

#Parametrisation of TCP sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
$tcp_src($j) set packetSize_ 552
}                   

#Schedule events for the FTP agents:
for {set i 1} {$i<=$NumbSrc} { incr i } {
$ns at $startT($i) "$ftp($i) start"
$ns at $Duration "$ftp($i) stop"
}