1. LAB 3 NS2 Preliminaries

2. Contents TCL/OTCl Fundamentals Creating Network Setting Connections Generating Traffic Inserting Errors Configuring for multicast Creating Wireless Nodes

3. Fundamentals of TCL A string-based command language. A few fundamental constructs and relatively little syntax, which makes it easy to learn. Designed to be a glue that assembles software building blocks into applications. Tcl is interpreted when the application runs. The interpreter makes it easy to build and refine your application in an interactive manner.

4. Example Script command arg1 arg2 arg3... puts stdout {Hello, World!}  Hello World! set a World puts stdout ”Hello $a! ” $a  Hello World! set b a  b = a set b $a  b = World set len [string length ns2work]  len = 7 set pi [expr 2*asin(1.0)]

5. Example Script proc name arglist body proc Diag {a b} { set c [expr sqrt($a * $a + $b * $b)] return $c } proc Factorial {x} { set i 1; set product 1 while {$i <= $x} { set product [expr $product * $i] incr i } return $product }

6. Basic otcl Class mom mom instproc init {age} { $self instvar age_ set age_ $age } mom instproc greet {} { $self instvar age_ puts “$age_ years old mom: How are you doing?” } Class kid -superclass mom kid instproc greet {} { $self instvar age_ puts “$age_ years old kid: What’s up, dude?” } set a [new mom 40] set b [new kid 10] $a greet  40 years old mom: How are you doing? $b greet  10 years old kid: What's up?

7. Creating Event Scheduler Create scheduler –set ns [new Simulator] Schedule event –$ns at – : any legitimate ns/tcl commands Start scheduler –$ns run

8. Tracing Trace packets on all links $ns trace-all [open test.out w] -- + 1 0 2 cbr 210 ------- 0 0.0 3.1 0 0 - 1 0 2 cbr 210 ------- 0 0.0 3.1 0 0 r 1.00234 0 2 cbr 210 ------- 0 0.0 3.1 0 0 Trace packets on all links in nam-1 format $ns namtrace-all [open test.nam w]

9. Creating Network Nodes set n0 [$ns node] set n1 [$ns node] Links & Queuing $ns duplex-link $n0 $n1 – : DropTail, RED, CBQ, FQ, SFQ, DRR $ns_ duplex-link-op

10. Computing routes Unicast –$ns rtproto – : Static, Session, DV, Manual $ns rtproto Static $ns rtproto Session $ns rtproto DV $n1 $n2 $n3 $ns rtproto LS $n1 $n2

11. Creating Connection: UDP 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

12. Creating Connection: TCP 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

13. Creating Traffic: On Top of TCP FTP set ftp [new Application/FTP] $ftp attach-agent $tcp $ns at “$ftp start” Telnet set telnet [new Application/Telnet] $telnet attach-agent $tcp

14. Creating Traffic: On Top of UDP CBR set src [new Application/Traffic/CBR] Exponential or Pareto on-off set src [new Application/Traffic/Exponential] set src [new Application/Traffic/Pareto] $src set packetSize_ 210 $src set burst_time_ 500ms $src set idle_time_ 500ms $src set rate_ 200k

15. Creating Traffic: Trace Driven Trace driven set tfile [new Tracefile] $tfile filename set src [new Application/Traffic/Trace] $src attach-tracefile $tfile : –Binary format –inter-packet time (msec) and packet size (byte)

16. Inserting Errors Creating Error Module set loss_module [new ErrorModel] $loss_module set rate_ 0.01 $loss_module unit pkt $loss_module ranvar [new RandomVariable/Uniform] $loss_module drop-target [new Agent/Null] Inserting Error Module $ns lossmodel $loss_module $n0 $n1

17. Network Dynamics Link failures –route changes reflected automatically –can emulate node failure

18. Four Models $ns rtmodel-at $n0 $n1 $ns rtmodel Trace $n0 $n1 $ns rtmodel $n0 $n1 : Deterministic, Exponential : [ ] [ ]

19. $ns rtmodel Exponential 0.8 1.0 1.0 $n1 $ns rtmodel Trace dynamics.trc $n2 $n3 v v 0.8123 link-up 3 5 v 3.5124 link-down 3 5 $ns rtmodel Deterministic 20.0 20.0 $node(1) $node(5)

20. Multicast - 5 components enable multicast capability configure multicast routing create a multicast group/sender create a multicast receiver attach traffic source

21. Enabling multicast capability set ns [new Simulator -multicast on] or $ns multicast (right after [new Simulator])

22. Configuring multicast routing $ns mrtproto : CtrMcast, DM, ST

23. Creating a multicast group set udp [new Agent/UDP] $ns attach-agent $n0 $udp set group [Node allocaddr] $udp set dst_addr_ $group

24. Creating a multicast receiver set rcvr [new Agent/NULL] $ns attach-agent $n1 $rcvr $ns at “$n1 join-group $rcvr $group”

25. Attaching a traffic source set cbr [new Application/Traffic/CBR] $cbr attach-agent $udp $ns at “$cbr start”

26. Case Study mcast.tcl

27. Wireless - 5 components setup node configuration –layer 3-2, layer 1, tracing, energy node coordinates node movements nam tracing

28. Setup set ns [new Simulator] set topo [new Topography] $topo load_flatgrid

29. Node Configuration: Layer 3-2 $ns node-config –adhocRouting –llType LL –ifqType Queue/DropTail/PriQueue –ifqLen –macType Mac/802_11 : DSDV, DSR, TORA, AODV

30. Node Configuring: Layer 1 $ns node-config –phyType Phy/WirelessPhy –antType Antenna/OmniAntenna –propType –channelType Channel/WirelessChannel –topoInstance $topo : Propagation/TwoRayGround, Propagation/FrissSpaceAttenuation

31. Node Configuration: Tracing $ns node-config –agentTrace –routerTrace –macTrace

32. Node Configuration: Energy $ns node-config –energyModel EnergyModel –initialEnergy –txPower –rxPower

33. Creating Nodes set mnode [$ns node]

34. Node Coordinates $mnode set X_ $mnode set Y_ $mnode set Z_ 0

35. Node Movement Disable random motion –$mnode random-motion 0 Specified –$ns at 1.0 “$mnode setdest ” Random –$ns at 1.0 “$mnode start”

36. Tracing at the beginning –$ns namtrace-all-wireless [open test.nam w] initialize nodes –$ns initial_node_position $mnode 20 at the end –$ns at “$ns nam-end-wireless ”

37. New Trace format $ns use-newtrace Event type –s: send, r: receive, d: drop, f: forward Node property tags –-Ni: node id, -Nx: node’s x-coordinate, -Ny: node’s y-coordinate, -Nz: node’s z-coordinate –-Ne: node energy level –-Nl: trace level, such as AGT, RTR, MAC –-Nw: reason for the event.

38. Case Studies multicast (mcast.tcl) wireless (wireless-udp.tcl)