Hi, You can see my code attached. I cann not get .nam output for it. I get node x is not defined warning. Any help is appreciated. Regards # ====================================================================== # Define options # ====================================================================== set val(chan) Channel/WirelessChannel ;# channel type set val(prop) Propagation/TwoRayGround ;# radio-propagation model set val(netif) Phy/WirelessPhy ;# network interface type set val(mac) Mac/802_11 ;# MAC type set val(ifq) Queue/DropTail/PriQueue ;# interface queue type set val(ll) LL ;# link layer type set val(ant) Antenna/OmniAntenna ;# antenna model set val(ifqlen) 50 ;# max packet in ifq set val(nn) 4 ;# number of mobilenodes set val(rp) DSDV ;# routing protocol # ====================================================================== # Main Program # ====================================================================== # # Initialize Global Variables # set ns_ [new Simulator] set tracefd [open simple4d.tr w] set namtrace [open simple4d.nam w] $ns_ use-newtrace # set up topography object set topo [new Topography] $topo load_flatgrid 200 200 $ns_ trace-all $tracefd $ns_ namtrace-all-wireless $namtrace 200 200 # # Create God # create-god $val(nn) # # Create the specified number of mobilenodes [$val(nn)] and "attach" them # to the channel. # Here two nodes are created : node(0) and node(1) # configure node $ns_ node-config -adhocRouting $val(rp) \ -llType $val(ll) \ -macType $val(mac) \ -ifqType $val(ifq) \ -ifqLen $val(ifqlen) \ -antType $val(ant) \ -propType $val(prop) \ -phyType $val(netif) \ -channelType $val(chan) \ -topoInstance $topo \ -agentTrace ON \ -routerTrace ON \ -macTrace OFF \ -movementTrace OFF for {set i 0} {$i < $val(nn) } {incr i} { set node_($i) [$ns_ node] $node_($i) random-motion 0 ;# disable random motion } # # Provide initial (X,Y, for now Z=0) co-ordinates for mobilenodes # $node_(0) set X_ 20.0 $node_(0) set Y_ 40.0 $node_(0) set Z_ 0.0 $node_(1) set X_ 20.0 $node_(1) set Y_ 20.0 $node_(1) set Z_ 0.0 $node_(2) set X_ 30.0 $node_(2) set Y_ 40.0 $node_(2) set Z_ 0.0 $node_(3) set X_ 30.0 $node_(3) set Y_ 20.0 $node_(3) set Z_ 0.0 # Setup traffic flow between nodes # TCP connections between node_(0) and node_(1) set tcp [new Agent/TCP] $tcp set class_ 2 set sink [new Agent/TCPSink] $ns_ attach-agent $node_(0) $tcp $ns_ attach-agent $node_(1) $sink $ns_ connect $tcp $sink set ftp [new Application/FTP] $ftp attach-agent $tcp $ns_ at 10.0 "$ftp start" set tcp [new Agent/TCP] $tcp set class_ 2 set sink [new Agent/TCPSink] $ns_ attach-agent $node_(2) $tcp $ns_ attach-agent $node_(3) $sink $ns_ connect $tcp $sink set ftp [new Application/FTP] $ftp attach-agent $tcp $ns_ at 10.0 "$ftp start" # # Tell nodes when the simulation ends # for {set i 0} {$i < $val(nn) } {incr i} { $ns_ at 100.0 "$node_($i) reset"; } $ns_ at 100.0 "stop" $ns_ at 100.01 "puts \"NS EXITING...\" ; $ns_ halt" proc stop {} { global ns_ tracefd $ns_ flush-trace close $tracefd } puts "Starting Simulation..." $ns_ run --------------------------------- Yahoo! Messenger with Voice. PC-to-Phone calls for ridiculously low rates. --------------------------------- How low will we go? Check out Yahoo! Messengers low PC-to-Phone call rates.