跑leach需要的

				# null.tcl
				# Author: Alexander Sayenko 
				# Dates: Mon, 24 Nov 2003
				# Notes: A script to show the use of Null plicy
				
				set ns [new Simulator]
				
				set cir  1000000
				set cir2 500000
				
				set client  [$ns node]
				set client2 [$ns node]
				set border [$ns node]
				set core [$ns node]
				set server [$ns node]
				
				$ns simplex-link $client2 $border 10Mb 2ms DropTail
				$ns simplex-link $client $border 10Mb 2ms DropTail
				$ns simplex-link $border $core 10Mb 2ms dsRED/edge
				$ns simplex-link $core $server 10Mb 2ms dsRED/core
				
				set agent  [new Agent/UDP]
				set agent2 [new Agent/UDP]
				
				set sink   [new Agent/Null]
				set sink2  [new Agent/Null]
				
				set appl [new Application/Traffic/CBR]
				$appl set rate_ [expr $cir+10000]
				
				set appl2 [new Application/Traffic/CBR]
				$appl2 set rate_ $cir2
				
				$client attach $agent
				$client2 attach $agent2
				
				$server attach $sink
				$server attach $sink2
				
				$ns connect $agent $sink
				$ns connect $agent2 $sink2
				
				$appl attach-agent $agent
				$appl2 attach-agent $agent2
				
				set qBC [[$ns link $border $core] queue]
				set qCS [[$ns link $core $server] queue]
				
				# -------------------------------------------------
				$qBC set NumQueues_ 1
				$qBC setNumPrec 2
				
				$qBC addPolicyEntry [$client id] [$server id] TokenBucket 10 $cir 500
				$qBC addPolicerEntry TokenBucket 10 11
				
				$qBC addPolicyEntry [$client2 id] [$server id] Null 20
				$qBC addPolicerEntry Null 20
				
				$qBC addPHBEntry 10 0 0
				$qBC addPHBEntry 11 0 1
				$qBC addPHBEntry 20 0 0
				
				$qBC configQ 0 0 4 10 0.1
				$qBC configQ 0 1 2 5 0.5
				# -------------------------------------------------
				
				$qCS set NumQueues_ 1
				$qCS setNumPrec 2
				
				$qCS addPHBEntry 10 0 0
				$qCS addPHBEntry 11 0 1
				$qCS addPHBEntry 20 0 0
				
				$qCS configQ 0 0 4 10 0.1
				$qCS configQ 0 1 2 5 0.5
				# -------------------------------------------------
				
				$ns at 0 "$appl start; $appl2 start"
				$ns at 5 "finish"
				
				proc finish {} {
				
				  global ns
				  global qBC qCS
				
				  $qBC printStats
				  $qBC printPolicyTable
				  $qBC printPolicerTable
				
				  $ns halt
				
				}
				
				$ns run