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NS-tutorial

NS-tutorial. 2003. 5. 14 통신 프로토콜 설계와 해석 HPMN Lab. 석사 2 학기 한제찬. Contents. Part I. NS(Network Simulator) 소개 NS(Network Simulator) reference site NS Status and Modules NS 설치 방법 - on window, on linux Part II. NS Architecture NS 구성 – C++, tcl Part III. Wired Simulation in NS

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NS-tutorial

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  1. NS-tutorial 2003. 5. 14 통신 프로토콜 설계와 해석 HPMN Lab. 석사 2학기 한제찬

  2. Contents • Part I. NS(Network Simulator) 소개 • NS(Network Simulator) reference site • NS Status and Modules • NS 설치 방법- on window, on linux • Part II. NS Architecture • NS 구성 – C++, tcl • Part III. Wired Simulation in NS • Part IV. Wireless Simulation in NS • Part V. Tracing & Monitoring • Trace file • nam HPMN Lab.

  3. Part I. NS Introduction

  4. Ns Goals • Support networking research and education • Protocol design, traffic studies, etc • Protocol comparison • Provide a collaborative environment • Freely distributed, open source • Share code, protocols, models, etc • Allow easy comparison of similar protocols • Increase confidence in results • More people look at models in more situations • Experts develop models • Multiple levels of detail in one simulator HPMN Lab.

  5. Ns Status • The most recent release (ns-2.26, Feb 2003) • Periodical release (ns-2.1b9a, July 2002) • Stability validation • http://www.isi.edu/nsnam/ns/ns-tests.html • Platform support • FreeBSD, Linux, Solaris, Windows and Mac HPMN Lab.

  6. Ns Functionalities • Wired • Routing DV, LS, PIM-SM • Transportation: TCP and UDP • Traffic sources:web, ftp, telnet, cbr, stochastic • Queuing disciplines:drop-tail, RED, FQ, SFQ, DRR • QoS: IntServ and Diffserv • Emulation • Wireless • Ad hoc routing and mobile IP • Directed diffusion, sensor-MAC • Tracing, visualization, various utilities HPMN Lab.

  7. “Ns” Components • Ns, the simulator itself • Nam, the network animator • Visualize ns (or other) output • Nam editor: GUI interface to generate ns scripts • Pre-processing: • Traffic and topology generators • Post-processing: • Simple trace analysis, often in Awk, Perl, or Tcl HPMN Lab.

  8. Ns Models • Traffic models and applications: • Web, FTP, telnet, constant-bit rate, real audio • Transport protocols: • unicast: TCP (Reno, Vegas, etc.), UDP • Multicast: SRM • Routing and queueing: • Wired routing, ad hoc rtg and directed diffusion • queueing protocols: RED, drop-tail, etc • Physical media: • Wired (point-to-point, LANs), wireless (multiple propagation models), satellite HPMN Lab.

  9. Installation(1/2) • Getting the pieces • Tcl/TK 8.x (8.3.2 preferred): http://resource.tcl.tk/resource/software/tcltk/ • Otcl and TclCL: http://otcl-tclcl.sourceforge.net • ns-2 and nam-1: http://www.isi.edu/nsnam/dist • Other utilities • http://www.isi.edu/nsnam/ns/ns-build.html • http://www.isi.edu/nsnam/dist HPMN Lab.

  10. Installation(2/2) • http://www.isi.edu/nsnam/ns/ns-build.html • Building ns on Linux • Source : ns-allinone-2.26.tar.gz • Building ns on windows • Source • tcl8.3.2.tar.gz • tk8.3.2.tar.gz • tclcl-src-1.0b12.tar.gz • otcl-1.0a8.tar.gz • ns-src-2.1b9a.tar.gz • Building ns-2/nam under cygwin HPMN Lab.

  11. Help and Resources • Ns and nam build questions • http://www.isi.edu/nsnam/ns/ns-build.html • Ns mailing list: ns-users@isi.edu • Ns manual and tutorial (in distribution) • TCL: http://dev.scriptics.com/scripting • Otcl tutorial (in distribution): ftp://ftp.tns.lcs.mit.edu/pub/otcl/doc/tutorial.html HPMN Lab.

  12. Part II. NS Architecture

  13. Ns Architecture • Uses both C++ and OTcl • Object-oriented (C++, OTcl) • Modular approach • Fine-grained object composition HPMN Lab.

  14. C++ and OTcl Separation • “data” / control separation • C++ for “data”: • per packet processing, core of ns • fast to run, detailed, complete control • OTcl for control: • Simulation scenario configurations • Periodic or triggered action • Manipulating existing C++ objects • fast to write and change HPMN Lab.

  15. Otcl and C++: The Duality • OTcl (object variant of Tcl) and C++ share class hierarchy • TclCL is glue library that makes it easy to share functions, variables, etc C++ C++/OTcl split objects otcl HPMN Lab.

  16. tclcl • The code to interface with the Otcl resides in the directory, ‘tclcl’ • The six classes defined in ‘tclcl/’ • Class Tcl • Class TclObject • Class TclClass • Class TclCommand • Class EmbeddedTcl • Class InstVar • Refer Chapter 3. OTcl Linkage of NS Manual HPMN Lab.

  17. Class hierarchy • Class hierarchy (contributed by Antoine Clerget) “http://www-sop.inria.fr/planete/software/ns-doc/ns-current/” HPMN Lab.

  18. Part III. Wired Simulation in NS

  19. Ns programming • Create the event scheduler • Turn on tracing • Create network • Create transport connection • Create traffic • Setup routing • Insert errors HPMN Lab.

  20. Creating Event Scheduler • Create event scheduler set ns [new Simulator] • Schedule events $ns at <time> <event> • <event>: any legitimate ns/tcl commands $ns at 5.0 “finish” • Start scheduler $ns run HPMN Lab.

  21. Creating Event Scheduler • Finish function 정의 proc finish {} { global ns nf tracefd $ns flush-trace close $nf close $tracefd exit 0 } $ns at <time> “finish” HPMN Lab.

  22. Turn on tracing • Packet tracing • On all links: set <변수명> [open filename mode] $ns trace-all $<변수명> Ex) $ns tracefd [open out.tr w] $ns trace-all $tracefd • Visualize trace in nam set 변수명 [open *.nam w] $ns namtrace-all $<변수명> HPMN Lab.

  23. Creating Network • Nodes set n0 [$ns node] set n1 [$ns node] • Links and queuing $ns <link_type> $n0 $n1 <bandwidth> <delay> <queue_type> • <link_type>: duplex-link, simplex-link • <queue_type>: DropTail, RED, CBQ, FQ, SFQ, DRR, diffserv RED queues Ex) $ns duplex-link $n0 $n1 0.1Mb 100ms DropTail HPMN Lab.

  24. Creating Network: LAN $ns make-lan <node_list> <bandwidth> <delay> <ll_type> <ifq_type> <mac_type> <channel_type> <ll_type>: LL <ifq_type>: Queue/DropTail, <mac_type>: MAC/802_3 <channel_type>: Channel HPMN Lab.

  25. Creating Connection and Traffic FTP/Telnet TCP connection TCP TCPsink Node 0 Node 1 Duplex link CBR/Exp UDP connection TCP NULL Node 0 Node 1 Duplex link HPMN Lab.

  26. 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 UDP details Chapter 30 of ns Manual Creating Connection and Traffic HPMN Lab.

  27. Creating Connection and Traffic • CBR set cbr0 [new Application/Traffic/CBR] • CBR details $cbr0 set packetSize_ 500 $cbr0 set interval_ 0.005 • Locate CBR on transport layer $cbr0 attach-agent $udp • Exponential or Pareto on-off set src [new Application/Traffic/Exponential] set src [new Application/Traffic/Pareto] HPMN Lab.

  28. 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 TCP details Chapter 31 of ns Manual Creating Connection and Traffic II HPMN Lab.

  29. Creating Connection and Traffic II • FTP set ftp [new Application/FTP] $ftp attach-agent $tcp • Telnet set telnet [new Application/Telnet] $telnet attach-agent $tcp HPMN Lab.

  30. Example1b.tcl • Trace file • Packet trace : out.tr • Nam trace : out.nam • Topology • Two nodes: n0, n1 • Duplex link • Udp and cbr Example1.tcl HPMN Lab.

  31. Example1b.tcl # Create NS simulator instance set ns [new simulator] # Create trace files - nam file set tf [open out.tr w] $ns trace-all $tf set nf [open out.nam w] $ns namtrace-all $nf # Create topology - nodes and links set n0 [$ns node] set n1 [$ns node] $ns duplex-link $n0 $n1 1Mb 10ms DropTail # Create transport protocol set udp0 [new Agent/UDP] $ns attach-agent $n0 $udp0 set null0 [new Agent/Null] $ns attach-agent $n1 $null0 $ns connect $udp0 $null0 # Create Traffic set cbr0 [new Application/Traffic/CBR] $cbr0 set packetsize_ 500 $cbr0 set interval_ 0.005 $cbr0 attach-agent $udp0 # Define finish function proc finish{} { global ns nf $ns flush-trace close $nf exit 0 } # Setup evnets $ns at 0.5 "$cbr0 start" $ns at 4.5 "$cbr0 stop" $ns at 5.0 "finish" # Run NS $ns run HPMN Lab.

  32. Inserting Errors • ErrorModel types • Class ErrorModel/Uniform • Class ErrorModel/Expo • Class ErrorModel/Empirical • Two state error model • Multi state error model HPMN Lab.

  33. Inserting Errors -Uniform • 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 HPMN Lab.

  34. Setup Routing • Unicast $ns rtproto <type> <type>: Static, Session, DV, cost, multi-path • Multicast $ns multicast (right after [new Simulator]) $ns mrtproto <type> <type>: CtrMcast, DM, ST, BST • Other types of routing supported: source routing, hierarchical routing HPMN Lab.

  35. Creating Traffic: Trace Driven • Trace driven set tfile [new Tracefile] $tfile filename <file> set src [new Application/Traffic/Trace] $src attach-tracefile $tfile <file>: • Binary format (native!) • inter-packet time (msec) and packet size (byte) HPMN Lab.

  36. Marking flows • $<agent name> set class_ <fid> ex) $udp0 set class_ 1 • $ns color <fid> <color> ex) $ns color 1 Blue HPMN Lab.

  37. Creating a larger topology • for 구문 for {변수 초기화} {조건} {변수 값 변경} { … } • 변수 초기화: set <변수 명> <값> • 조건: $<변수 명> • 변수 값 변경 Ex) for {set I 0} {$I < 7} {incr I} { set n($I) [$ns node] } Ex) for {set I 0} {$I <7} {incr I} { $ns duplex-link $n($I) $n([expr ($I+1)%7]) 1Mb 10ms DropTail } HPMN Lab.

  38. Link failure • 특정 시각에 link 끊기 $ns rtmodel-at <time> down $<node name> $<node name> • 특정 시각에 끊긴 link 다시 연결하기 $ns trmodel-at <time> up $<node name> $<node name> HPMN Lab.

  39. IV. Wireless Simulation in NS

  40. Running Wireless Simulations in ns • define components and options of mobile nodes • creating an instance of the simulator • setup trace support • create a topology object • create the object GOD • create mobile nodes • create agent and traffic • setup Event HPMN Lab.

  41. ad-hoc network(1/8) • define components of mobile nodes At the beginning of a wireless simulation, we need to define the type for each of these network components. HPMN Lab.

  42. ad-hoc network : Ex_wireless1.tcl (2/8) • creating an instance of the simulator Set ns_ [new Simulator] • setup trace support Set tracefd [open ex_wl1.tr w] $ns_ trace-all $tracefd • create a topology object Set topo [new Topography] $topo load_flatgrid 500 500 • create the object GOD Create-god $val(nn) HPMN Lab.

  43. ad-hoc network : Ex_wireless1.tcl(3/8) • Topology Object : keep track of movement of mobile nodes • God (General Operations Director) : the object that is used to store global information about the state of the environment & network • total number of mobile nodes • a table of shortest number of hops required to reach from one node to another. • The next hop information is normally loaded into god object from movement pattern files, before simulation begins. • the God object is called internally by MAC objects in mobile nodes. HPMN Lab.

  44. # $ns_ node-config -addressingType flat or hierarchical or expanded # -adhocRouting DSDV or DSR or TORA # -llType LL # -macType Mac/802_11 # -propType "Propagation/TwoRayGround" # -ifqType "Queue/DropTail/PriQueue" # -ifqLen 50 # -phyType "Phy/WirelessPhy" # -antType "Antenna/OmniAntenna" # -channelType "Channel/WirelessChannel" # -topoInstance $topo # -energyModel "EnergyModel" # -initialEnergy (in Joules) # -rxPower (in W) # -txPower (in W) # -agentTrace ON or OFF # -routerTrace ON or OFF # -macTrace ON or OFF # -movementTrace ON or OFF ad-hoc network : Ex_wireless1.tcl (4/8) • create mobile nodes • Node configuration HPMN Lab.

  45. ad-hoc network : Ex_wireless1.tcl (5/8) 2. Create the 2 mobile nodes set node_(0) [$ns_ node ] $node_(0) random-motion 0 ;# disable random motion set node_(1) [$ns_ node ] $node_(1) random-motion 0 3. Give nodes position to start with $node_(0) set X_ 5.0 $node_(0) set Y_ 2.0 $node_(0) set Z_ 0.0 $node_(1) set X_ 390.0 $node_(1) set Y_ 385.0 $node_(1) set Z_ 0.0 HPMN Lab.

  46. ad-hoc network : Ex_wireless1.tcl (6/8) 4. Set node movements $ns_ at <time> “$<node name> setdest <목적위치> <속도> Ex) $ns_ at 50.0 "$node_(1) setdest 25.0 20.0 15.0“ $ns_ at 10.0 "$node_(0) setdest 20.0 18.0 1.0“ HPMN Lab.

  47. ad-hoc network : Ex_wireless1.tcl (7/8) • create agent and traffic 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" HPMN Lab.

  48. ad-hoc network : Ex_wireless1.tcl (8/8) • Define Events • Reset mobile nodes $ns_ at 150.0 “$node_(0) reset” $ns_ at 150.0 “$node_(1) reset” • Simulation stop $ns_ at 150.0001 "stop" $ns_ at 150.0002 "puts \"NS EXITING...\" ; $ns_ halt“ proc stop {} { global ns_ tracefd close $tracefd } puts "Starting Simulation..." $ns_ run HPMN Lab.

  49. Using node-movement files & traffic-pattern files • Node-movement file • CMU’s node-movement generator • Traffic-pattern file • CMU’s TCP/CBR traffic generator • Load node-movement file & traffic-generator file(in tcl script file) Ex) source “../mobility/scene/scen-3-test” source “../mobility/scene/cbr-3-test” HPMN Lab.

  50. Creating wired-cum-wireless in ns • a simple wired-cum-wireless scenario • 2 Wired nodes: • w(0),w(1) • 3 mobile nodes • 1 base-station node HPMN Lab.

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