[ns] ns2 emulation - urgent help needed
vngo at engmail.uwaterloo.ca
Fri Aug 11 12:03:03 PDT 2006
I am a undergraduate research student at the University of Waterloo, Ontario
and am a complete beginner to NS2 (and even Linux). I'm working for a
research group and my task is to demonstrate a very basic emulation example
next week just to show that it is possible to use ns2 to emulate. I've been
trying to get any simple emulation script to work for the past few weeks but
have failed. I'm sure it would take an expert just a few minutes to
write a couple lines of code to do this. Most explainations I have read to
similar problems are even too advanced for my understanding either in terms
NS2 or Linux. If someone could please help me on a student level that would
I am using a Linux machine and so far I have downloaded and installed the
allinone ns-2.29. I have also googled for some simple example emulation
For example, I found this one:
# Create simulator
set ns [new Simulator]
$ns use-scheduler RealTime
# Emulator address
set me [exec hostname]
# Packet input
set bpf0 [new Network/Pcap/Live]
$bpf0 set promisc_ true
set nd0 [$bpf0 open readonly fxp0]
set filt "(not ip host $me)"
$bpf0 filter $filt
# Packet output
set ipnet [new Network/IP]
$ipnet open writeonly
# Input agent
set pfa [new Agent/Tap]
$pfa network $bpf0
# Output agent
set ipa [new Agent/Tap]
$ipa network $ipnet
# ICMP ECHO agent
set echoagent [new Agent/PingResponder]
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
$ns simplex-link $n0 $n2 100Mb 1000ms DropTail
$ns simplex-link $n2 $n1 100Mb 1000ms DropTail
$ns attach-agent $n0 $pfa
$ns attach-agent $n1 $ipa
$ns attach-agent $n2 $echoagent
$ns simplex-connect $pfa $echoagent
$ns simplex-connect $ipa $echoagent
# Wait for ping to come in...
When I try running this script I get a message that says:
invalid command name "Network/Pcap/Live"
"Network/Pcap/Live create o_11 "
invoked from within
"catch "$className create $o $args" msg"
(procedure "new" line 3)
invoked from within
"set bpf0 [new Network/Pcap/Live]"
(file "./vince/emu1.tcl" line 12)
Can anyone help me with this problem please? Since I am not yet an ns2
expert, I don't know all too well how that code works. I believe it is a
responder. All I need is a very simple emulation example to show that it
works so any other suggestions or example scripts would be great!
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