1. Choe, Hyun Jung (Stella)
UTA
CSE 4346/5346 Networks II
NS-2 Tutorial
- Part 2 -
Choe, Hyun Jung (Stella)
Spring 2008
Networks II
Department of Computer Science and Engineering The University of Texas at Arlington
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2. GTA Office Hours Monday and Thursday 2:30 PM ~ 3:30 PM NH 239
UTA
CSE 4346/5346 Networks II
GTA Office Hours
Monday and Thursday
2:30 PM ~ 3:30 PM
NH 239
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3. Outline Simulation Examples Project Q & A Analysis example: awk
UTA
CSE 4346/5346 Networks II
Outline
Simulation Examples
Visualization: nam, xgraph
Analysis example: awk
Project
Overview
Submission Guideline
Q & A
Today, I will show you some ns2 simulation examples and discuss class project.
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4. UTA
Simulation Examples
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5. simple.tcl #Create a simulator object set ns [new Simulator]
UTA
CSE 4346/5346 Networks II
simple.tcl
#Create a simulator object
set ns [new Simulator]
#Open the NAM trace file
set nf [open out.nam w]
$ns namtrace-all $nf
# Open trace file
set tf [open out.tr w]
$ns trace-all $tf
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6. #Define a 'finish' procedure proc finish {} { global ns nf
UTA
CSE 4346/5346 Networks II
#Define a 'finish' procedure
proc finish {} {
global ns nf
$ns flush-trace
#Close the trace file
close $nf
exit 0 }
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7. #Create links between the nodes
UTA
CSE 4346/5346 Networks II
#Create four nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
#Create links between the nodes
$ns duplex-link $n0 $n2 2Mb 10ms DropTail
$ns duplex-link $n1 $n2 2Mb 10ms DropTail
$ns duplex-link $n2 $n3 1.7Mb 20ms DropTail
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8. #Setup a TCP connection set tcp [new Agent/TCP]
UTA
CSE 4346/5346 Networks II
#Setup a TCP connection
set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n3 $sink
$ns connect $tcp $sink
$tcp set fid_ 1
#Setup a FTP over TCP connection
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ftp set type_ FTP
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9. #Setup a UDP connection set udp [new Agent/UDP]
UTA
CSE 4346/5346 Networks II
#Setup a UDP connection
set udp [new Agent/UDP]
$ns attach-agent $n1 $udp
set null [new Agent/Null]
$ns attach-agent $n3 $null
$ns connect $udp $null
$udp set fid_ 2
#Setup a CBR over UDP connection
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set type_ CBR
$cbr set packet_size_ 1000
$cbr set rate_ 1mb
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10. #Schedule events for the CBR and FTP agents $ns at 0.1 "$cbr start"
UTA
CSE 4346/5346 Networks II
#Schedule events for the CBR and FTP agents
$ns at 0.1 "$cbr start"
$ns at 1.0 "$ftp start"
$ns at 4.0 "$ftp stop"
$ns at 4.5 "$cbr stop"
#Detach tcp and sink agents (not really necessary)
$ns at 4.5 "$ns detach-agent $n0 $tcp ; $ns detach-agent $n3 $sink"
#Call the finish procedure after 5 seconds of simulation time
$ns at 5.0 "finish"
(Manual - 18p.)
NS simulator is based on two languages: c++ and Otcl (Tool Command Language)
There are two class hierarchies: the compiled c++ hierarchy and and the interpreted Otcl one, with one to one correspondence between them.
The compiled c++ hierarchy allows us to achieve efficiency in the simulation and faster execution times reducing event processing time.
This is particularly useful for the detailed definition and operation of protocols.
TCL is easy to use with a very simple syntaxes and it allows a very easy integration with other languages.
We can defined a particular network topology, the specific protocols and applications that we wish to simulate in the Otcl script.
The behavior is already defined in the compiled hierarchy.
Also we can define the form of the output that we wish to obtain from the simulation.
We will discuss how to program using Tcl later.
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11. #Print CBR packet size and interval
UTA
CSE 4346/5346 Networks II
#Print CBR packet size and interval
puts "CBR packet size = [$cbr set packet_size_]"
puts "CBR interval = [$cbr set interval_]"
#Run the simulation
$ns run
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12. TCP: Default Parameters
UTA
CSE 4346/5346 Networks II
TCP: Default Parameters
# max bound on window size
Agent/TCP set window_ 100
# congestion windows
Agent/TCP set cwnd_ 10
# initial/reset value of cwnd
Agent/TCP set windowInit_ 1
# MSS size
Agent/TCP set packetSize_ 1500
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13. NAM #Define a 'finish' procedure proc finish {} { global ns nf
UTA
CSE 4346/5346 Networks II
NAM
#Define a 'finish' procedure
proc finish {} {
global ns nf
$ns flush-trace
#Close the trace file
close $nf
#Execute NAM on the trace file
exec nam out.nam &
exit 0 }
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14. awk Set awkCodeTr { if ( NF == 12 ) { event =$1 time = $2
UTA
CSE 4346/5346 Networks II
awk
Set awkCodeTr {
if ( NF == 12 ) {
event =$1
time = $2
if (event = “d”) {
dropCount += 1;
print time, dropCount >> “drop.a”; }
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15. UTA
CSE 4346/5346 Networks II
XGRAPH
exec xgraph -bb -tk -x time -y lossRatio -bg White -geometry 540x405 /tmp/team3/fs.xg &
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16. Using Variables set testTime 60.0 …… $ns at $testTime “$cbr0 stop”
UTA
CSE 4346/5346 Networks II
Using Variables
set testTime 60.0 ……
$ns at $testTime “$cbr0 stop”
$ns at $testTime “$cbr1 stop”
$ns at $testTime “tcp stop”
$ns at [expr $testTime + 1.0] “finish”
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17. UTA
CSE 4346/5346 Networks II
DiffServ
To provide QoS by dividing traffic into different categories, scheduling packets accordingly
Major components
Policy
Edge router
Core router
Implementation
virtual queues, causing packets from one virtual queue to be dropped more frequently than packets from another.
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18. DiffServ Configuration
UTA
CSE 4346/5346 Networks II
DiffServ Configuration
$dsredq set numQueues_ 1
$dsredq setNumPrec 2
$dsredq configQ
$dsredq setSchedularMode WRR
$ns simplex-link $edge $core 10Mb 5ms dsRED/edge
$ns simplex-link $core $edge 10Mb 5ms dsRED/core
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19. # Set DS RED parameters from Edge to Core:
UTA
CSE 4346/5346 Networks II
# Set DS RED parameters from Edge to Core:
set qEC [[$ns link $edge $core] queue]
$qEC meanPktSize $packetSize
$qEC set numQueues_ 1
$qEC setNumPrec 2
$qEC addPolicyEntry [$s1 id] [$dest id] TokenBucket 10 $cir0 $cbs0
$qEC addPolicyEntry [$s2 id] [$dest id] TokenBucket 10 $cir1 $cbs1
$qEC addPolicerEntry TokenBucket 10 11
$qEC addPHBEntry
$qEC addPHBEntry
$qEC configQ
$qEC configQ
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20. # Set DS RED parameters from Core to Edge:
UTA
CSE 4346/5346 Networks II
# Set DS RED parameters from Core to Edge:
set qCE [[$ns link $core $e1] queue]
$qCE meanPktSize $packetSize
$qCE set numQueues_ 1
$qCE setNumPrec 2
$qCE addPHBEntry
$qCE addPHBEntry
$qCE configQ 93
$qCE configQ
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21. UTA
Project
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22. UTA
CSE 4346/5346 Networks II
Phase 1
Purpose
To be familiar with NS2
To master how to configure network topology
Steps
Setup system environment
Run specified two example files
Establish specified network topology
Establish traffic flows
Submit your file
You are free to experiment various parameters if your simulation satisfies requirements, specified topology and traffic flows!
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23. Phase 2 Purpose Requirements
UTA
CSE 4346/5346 Networks II
Phase 2
Purpose
To know how to trace/monitor/analyze simulation results
To understand different characteristics of TCP and UDP congestion control
Requirements
Simulate your program with specified parameter values
Generate result graphs to verify the performance
Compare and analyze the results
Make a comprehensive analysis report
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24. Topology CSE 4346/5346 Networks II CReWMaN UTA 5 Mbps, 5/10ms
Host 1
Host 2
Host 3
Host 4
Host 5
Host 6
5 Mbps, 5/10ms
2 Mbps, 10ms
1 Mbps, 10ms
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25. Phase 3 Purpose Requirement
UTA
CSE 4346/5346 Networks II
Phase 3
Purpose
To help the student master the concepts and practices quality of service (QoS) and traffic management
Requirement
Use Differentiated Service modules
Try to satisfy specified QoS requirements
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26. Phase 4 Purpose Requirement
UTA
CSE 4346/5346 Networks II
Phase 4
Purpose
To help the student master the concepts and practices of traffic engineering
To compare and analyze the relationship of measured performance metrics
Requirement
Measure additional QoS metrics
Compare the results
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27. Submission Format Analysis Report Readme phase#_last name.*
UTA
CSE 4346/5346 Networks II
Submission Format
Analysis Report
*.ps or *.pdf
Readme
*.txt
phase#_last name.*
phase4_choe.tcl, phase4_choe.ps, phase4_choe.tar.gz
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28. Compression mkdir phase1 cp files phae1 tar –cvf project.tar ./phase1
UTA
CSE 4346/5346 Networks II
Compression
mkdir phase1
cp files phae1
tar –cvf project.tar ./phase1
gzip phase1.tar
phase1.tar.gz
Please DO NOT include trace files!
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29. Hard Deadline Hard copy Soft copy
UTA
CSE 4346/5346 Networks II
Hard Deadline
Hard copy
to Gergely Záruba prior to the beginning of class on the due date
Soft copy
to prior to the beginning of class on the due date
Late submissions will receive 10% (of the total possible grade) deduction. They will also be amortized 20% (of the total possible grade) each day after the assignment was due.
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