跑leach需要的

				set opt(tr) out				set opt(namtr)	"test-lan-1.nam"				set opt(seed)	0				set opt(stop)	3				set opt(node)	8								set opt(qsize)	10				set opt(bw)	    1Mb				set opt(delay)	100ms				set opt(ll)	    LL				set opt(ifq)	  Queue/DropTail				set opt(mac)	  Mac/802_3				set opt(chan)	  Channel				set opt(tcp)	  TCP/Reno				set opt(sink)	  TCPSink				set opt(app)	  FTP								proc finish {} {					global env nshome pwd					global ns opt					$ns flush-trace					exit 0				}								proc create-trace {} {					global ns opt								  if [file exists $opt(tr)] {				    catch "exec rm -f $opt(tr) $opt(tr)-bw [glob $opt(tr).*]"				  }								  set trfd [open $opt(tr) w]				  $ns trace-all $trfd					if {$opt(namtr) != ""} {						$ns namtrace-all [open $opt(namtr) w]					}				  return $trfd				}								proc create-topology {} {					global ns opt					global lan node source node0									set num $opt(node)					for {set i 0} {$i < $num} {incr i} {						set node($i) [$ns node]						lappend nodelist $node($i)					}									set lan [$ns newLan $nodelist $opt(bw) $opt(delay) \							-llType $opt(ll) -ifqType $opt(ifq) \							-macType $opt(mac) -chanType $opt(chan)]									set node0 [$ns node]					$ns duplex-link $node0 $node(0) 1Mb 100ms DropTail									$ns duplex-link-op $node0 $node(0) orient right								}								## MAIN ##				set ns [new Simulator]				set trfd [create-trace]								create-topology								set tcp0 [$ns create-connection TCP/Reno $node0 TCPSink $node(7) 0]				$tcp0 set window_ 15								set ftp0 [$tcp0 attach-app FTP]								### set operations				$ns at 0.0 "$ftp0 start"				$ns at $opt(stop) "finish"								### take snapshots				foreach i "0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 \				1.2 1.5 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8" {						$ns at $i "$ns snapshot"				}								### take snapshot operations				$ns at 2.9 "$ns terminate-nam"								$ns run