TNK092: Network Simulation - Nätverkssimulering Lecture #1: Course basics and a first taste of NS2 Vangelis Angelakis Ph.D.

Basic Course Information Examiner: Prof. Di Yuan Seminars: Dr. Vangelis Angelakis Labs: Ms. Qing He 6 ECTS, Load distribution:  Lab assignments: 2/6  Project work: 4/6 Subscribe to the course mailing list!! Webpage at: 2

Lectures 1.Course basics and first NS2 steps. 2.Manipulating results and adding modules 3.TCP/IP in NS2 4.Routing and network Dynamics 5.Wireless Networking Simulation 6.Wired & Wireless [sept. 21] backup lecture date. 3 [ aug. 28 ] [ aug. 29 ] [ aug. 31 ] [ sept. 4 ] [ sept. 5 ] [ sept. 12 ]

Assignments & Lab sessions 1.Learning to handle NS2 2.Setting up a new module in NS2 3.TCP/IP 4.Wireless networking 4 (+1) Lab sessions: Give you assistance on given assignment The 2 first give you hints & the basic steps on  how to proceed with it  what to expect The 2 last expect you to have done most of the job by then  assistive role. At the end of a lab session you DELIVER the report on the previous lab assignment  i.e.: on the session of Tue. Sept. 11 th, you are expected to deliver a report on the lab assignment discussed in the session of Sept. the 4 th. 4 [ sept. 4 ] [ sept. 11 ] [ oct. 2] [oct. 16 ]

Lab Groups and Project Teams For the Labs you MUST:  Select a lab partner  DEADLINE: TUESDAY, Sept. 4 5 I M P O R T A N T

Project 6 Implementation of (recent) research papers, with simulatory results Available on the course webpage from Tuesday, Sept. 11 th By Tuesday SEP :59 the course list (+ me) stating:  The names of TWO (2) students forming a project group  A list of 2-3 papers that the group is interested in IN ORDER OF PREFERENCE  Assignment of papers will be done in a first-come-first served manner, BUT:  Some groups may be assigned the same paper Such groups MUST work separately Reports and codes of these groups will be compared to identify integrity issues.

Project Deliverables 7 1.Project PROPOSAL By TUESDAY SEP. 30: NO extensions a brief summary identifying the paper’s KEY IDEA and the MAIN RESULT a list of the key points to implement that will illustrate them a list of the key system parameters, as the ones contained in the paper along with potential added assumptions 2.FINAL Report By SUNDAY OCT. 21: NO extensions  NS2 Implementation  Written 5-page (double-column) report  If FAIL deadlines for project resubmission (retake): Jan. 20, 2013 Aug. 25, Details on the course website

Other timeslots 1.lab time exceeding the assignments: One extra session [ Oct. 16] 2.Project tutorial sessions on a project group need-to-do basis i.e. BY APPOINTMENT! Sept 21: 8:15-10:15 Oct. 3: 17:15-19:15 Oct. 9: 13:15-17:15 Further tutorial may be arranged (upon availability only) by further arrangements 8

Some resources NS simulator for beginners: NS by example: The ns-2 wiki, user information: Getting started with ns-2: 9

Installation For Linux (Redhat, Ubuntu), FreeBSD, or other,  gcc needed  download ns-allinone software package, unzip (tar)  building ns from the sources (./install)  remember the enviromental variables (.bashrc in your own directory) For Windows  using Vmware Player (Free) will be the one used later on for the Lab download the ubuntu image for vmware, and install ns on your linux system: DETAILED INSTRUCTIONS ON THE COURSE WEB-PAGE  using Cygwin (Free) install Cygwin ( install all the packages if you don’t know which one you need instead of the defaut one download nsallinonesoftware package, unzip (tar) to one directory build ns source (./install) remember the enviromental variable (.bashrc) See Lab instructions or NS2 homepage for detailed information 10

NS2 Hello World! (hello.tcl) set ns [new Simulator] $ns at 1 “puts \“Hello World!\”” $ns at 1.5 “exit” $ns run $ $ ns hello.tcl Hello World! $ | 11

Tcl programming fundamentals 1/4 # This is a comment,the tcl interpreter will not “see” it set b 0 assigns to b the value 0 set x $a assigns to variable ‘ x ’ the value of variable ‘ a ’  To use the value assigned to a variable, we use the $ sign before the variable. set x [expr $a + $b]  A mathematical operation is done using the expr (ession) command. set myFilePtr [open my_filename w] opens my_filename for writing and gives you the pointer myFilePtr 12

Tcl programming fundamentals 2/4 puts $myFilePtr "text"  each time the puts command is used, a new line is started.  To avoid new line, one has to add -nonewline after puts  Tabulating is done by inserting \t puts "[expr 1/60]" will print ‘0’ on the screen  In Tcl the variables have no specific type, so a variable can be a string or an integer depending on the value you assign to it. puts "[expr 1.0/60.0]" to get the correct result exec xgraph data & Executes the unix program xgraph with input the file data. the & is used for background running 13

Tcl programming fundamentals 3/4 if { expression } { } else { }  The “ if ” command can be nested with other “ if ”s and with “ else ”s that can appear in the ” ” part  To test for equality, we use ==  For inequality, we use != for {set i 0} {$i < 5} {incr i} { } 14

Tcl programming fundamentals 4/4 proc blue { par1 par2... } { global var1 var2 return $something } This procedure is called by typing: blue x y in our tcl script  The values of x and y will be used by the procedure for par1 and par2. If par1 and par2 are changed within the procedure, this will not affect the values of x and y at the caller level (…“by value” argument passing)  On the other hand, if we wish the procedure to be able to affect directly variables external to it, we have to declare these variables as " global ". In the above example these are var1 and var2 15

TCL basic #1 16

TCL basic #2 17 fmod : Return the remainder after dividing expression x by expression y. break : could be used here... Notice there is a TCL commands wiki at:

Basic scripting: initialization & termination 1. Create a Simulator object set ns [new Simulator] The finish procedure: Flushing & closing the traces proc finish{} { global ns trc_file nam_file $ns flush-trace close trc_file close nam_file exec nam out.nam & exit 0 } 2. Output Traces: set file1 [open out.tr w] $ns trace-all $trc_file Data trace for all links set file2 [open out.nam w] $ns nametrace-all $nam_file Visual trace using the nam file format

Definition of nodes & links Create nodes set n0 [$ns node] set n1 [$ns node] Link the nodes Format follows: duplex-link $n0 $n1 e.g.: $ns duplex-link $n0 $n1 1Mb 10ms 19

Definition of nodes & links: a simplex link 20

An example Create nodes 21 Check: ns-default.tcl Find there default value

Basic networking scripts An ”automated” topology example for {set i 0} {$i < 7} {incr i} { set n($i) [$ns node] } for {set i 0} {$i < 7} {incr i} { $ns duplex-link $n($i) $n([expr($i+1)%7]) 1Mb 10ms RED } 22

Agents and applications Creating Data Connections  TCP set tcp [new Agent/TCP] set tcpsink [new Agent/TCPSink] $ns attach-agent $n0 $tcp $ns attach-agent $n1 $tcpsink $ns connect $tcp $tcpsink  UDP set udp [new Agent/UDP] set null [new Agent/NULL] $ns attach-agent $n0 $udp $ns attach-agent $n1 $null $ns connect $udp $null 23 n1 n0 tcp/udp sink

Basic Scripts Generating Traffic  FTP set ftp [new Application/FTP] $ftp attach-agent $tcp  Telnet set telnet [new Application/Telnet] $telnet attach-agent $tcp  CBR set src [new Application/Traffic/CBR]  Exponential, or Pareto on-off set src [new Application/Traffic/Exponential] set src [new Application/Traffic/Pareto] n1 n0 tcp ftp sink

Basic Scripts Insert Link dynamics Creating Error Module set loss_module[new ErrorModel] $loss_moduleset rate_ 0.01 $loss_moduleunit pkt $loss_module ranvar[new RandomVariable/Uniform] $loss_moduledrop-target [new Agent/Null] Inserting an Error Module $ns lossmodel $loss_module$n0 $n1 25

Basic Scripts Schedule Events and Run Simulation  Schedule Events $ns at  : any legitimate ns/tcl command $ns at 0.5 “$cbr start” $ns at 4.5 “$cbr stop”  Call ‘finish’ $ns at 5.0 “finish”  Run the simulation $ns run 26

Visualizing NAM 27 Remember this:

Visualizing NAM 28

Visualizing NAM Nodes  Color $node color red  Shape (can’t be changed after simulation starts) $node shape box (circle, box, hexagon)  Label (single string) $ns at 1.1 “$n0 label \”web cache 0\”” 29

Visualizing NAM Links  Color $ns duplex-link-op $n0 $n1 color "green”  Label $ns duplex-link-op $n0 $n1 label “backbone" 30

Visualizing NAM Layout  “Manual” layout: specify everything $ns duplex-link-op $n(0) $n(1) orient right $ns duplex-link-op $n(1) $n(2) orient right $ns duplex-link-op $n(2) $n(3) orient right $ns duplex-link-op $n(3) $n(4) orient 60deg  If anything missing  automatic layout 31

Example 1 32

Example 1 33

Example 2 #Create a simulator object set ns [new Simulator] #Open the nam trace file set nf [open out.nam w] $ns namtrace-all $nf #Define a 'finish' procedure proc finish {} { global ns nf $ns flush-trace #Close the trace file close $nf #Execute nam on the trace file exec nam out.nam & exit 0 } #Create two nodes set n0 [$ns node] set n1 [$ns node] #Create a duplex link between the nodes $ns duplex-link $n0 $n1 1Mb 10ms DropTail 34 # #Create a UDP agent and attach it to node n0 set udp0 [new Agent/UDP] $ns attach-agent $n0 $udp0 # Create a CBR traffic source and attach it to udp0 set cbr0 [new Application/Traffic/CBR] $cbr0 set packetSize_ 500 $cbr0 set interval_ $cbr0 attach-agent $udp0 #Create a Null agent (a traffic sink) and attach it to node n1 set null0 [new Agent/Null] $ns attach-agent $n1 $null0 #Connect the traffic source with the traffic sink $ns connect $udp0 $null0 #Schedule events for the CBR agent $ns at 0.5 "$cbr0 start" $ns at 4.5 "$cbr0 stop" #Call the finish procedure after 5 seconds of simulation time $ns at 5.0 "finish" #Run the simulation $ns run

Visualizing NAM 35

Example 3 #Create a simulator object set ns [new Simulator] #Define different colors for data flows $ns color 1 Blue $ns color 2 Red #Open the nam trace file set nf [open out.nam w] $ns namtrace-all $nf #Define a 'finish' procedure proc finish {} { global ns nf $ns flush-trace #Close the trace file close $nf #Execute nam on the trace file exec nam out.nam & exit 0 } #Create four nodes set n0 [$ns node] set n1 [$ns node] set n2 [$ns node] set n3 [$ns node] 36 #Create links between the nodes $ns duplex-link $n0 $n2 1Mb 10ms DropTail $ns duplex-link $n1 $n2 1Mb 10ms DropTail $ns duplex-link $n3 $n2 1Mb 10ms SFQ $ns duplex-link-op $n0 $n2 orient right-down $ns duplex-link-op $n1 $n2 orient right-up $ns duplex-link-op $n2 $n3 orient right #Monitor the queue for the link between node 2 and node 3 $ns duplex-link-op $n2 $n3 queuePos 0.5 #Create a UDP agent and attach it to node n0 set udp0 [new Agent/UDP] $udp0 set class_ 1 $ns attach-agent $n0 $udp0 # Create a CBR traffic source and attach it to udp0 set cbr0 [new Application/Traffic/CBR] $cbr0 set packetSize_ 500 $cbr0 set interval_ $cbr0 attach-agent $udp0

Example 3 #Create a UDP agent and attach it to node n1 set udp1 [new Agent/UDP] $udp1 set class_ 2 $ns attach-agent $n1 $udp1 # Create a CBR traffic source and attach it to udp1 set cbr1 [new Application/Traffic/CBR] $cbr1 set packetSize_ 500 $cbr1 set interval_ $cbr1 attach-agent $udp1 #Create a Null agent (a traffic sink) and attach it to node n3 set null0 [new Agent/Null] $ns attach-agent $n3 $null0 #Connect the traffic sources with the traffic sink $ns connect $udp0 $null0 $ns connect $udp1 $null0 #Schedule events for the CBR agents $ns at 0.5 "$cbr0 start" $ns at 1.0 "$cbr1 start" $ns at 4.0 "$cbr1 stop" $ns at 4.5 "$cbr0 stop" #Call the finish procedure after 5 seconds of simulation time $ns at 5.0 "finish" #Run the simulation $ns run 37

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Example 4 #Create a simulator object set ns [new Simulator] #Tell the simulator to use dynamic routing $ns rtproto DV #Open the nam trace file set nf [open out.nam w] $ns namtrace-all $nf #Define a 'finish' procedure proc finish {} { global ns nf $ns flush-trace #Close the trace file close $nf #Execute nam on the trace file exec nam out.nam & exit 0 } #Create seven nodes for {set i 0} {$i < 7} {incr i} { set n($i) [$ns node] } #Create links between the nodes for {set i 0} {$i < 7} {incr i} { $ns duplex-link $n($i) $n([expr ($i+1)%7]) 1Mb 10ms DropTail } 39 #Create links between the nodes for {set i 0} {$i < 7} {incr i} { $ns duplex-link $n($i) $n([expr($i+1)%7]) 1Mb 10ms DropTail } #Create a UDP agent and attach it to node n(0) set udp0 [new Agent/UDP] $ns attach-agent $n(0) $udp0 # Create a CBR traffic source and attach it to udp0 set cbr0 [new Application/Traffic/CBR] $cbr0 set packetSize_ 500 $cbr0 set interval_ $cbr0 attach-agent $udp0 #Create a Null agent (a traffic sink) #and attach it to node n(3) set null0 [new Agent/Null] $ns attach-agent $n(3) $null0 #Connect the traffic source with the traffic sink $ns connect $udp0 $null0 #Schedule events for the CBR agent # and the network dynamics $ns at 0.5 "$cbr0 start" $ns rtmodel-at 1.0 down $n(1) $n(2) $ns rtmodel-at 2.0 up $n(1) $n(2) $ns at 4.5 "$cbr0 stop" #Call the finish procedure after 5 seconds #of simulation time $ns at 5.0 "finish" #Run the simulation $ns run

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