University of Texas at Arlington CSE 5346/4346 High Performance Networks 1 NS-2 Tutorial Choe, Hyun Jung (Stella) Spring 2008 Spring 2008 High Performance Networks Department of Computer Science and Engineering The University of Texas at Arlington

University of Texas at Arlington CSE 5346/4346 High Performance Networks 2 Outline NS-2 Overview How to Run NS-2 How to Program Simulation Examples Project Overview Q & A

University of Texas at Arlington NS-2 Overview

University of Texas at Arlington CSE 5346/4346 High Performance Networks 4 What is NS-2? VINT Project - UC Berkeley, LBL, USC/ISI, and Xerox PARC Goals - Support networking research and education - Freely distributed, open source  Share code, protocols, models, etc a Discrete Event Simulator Link layer and up Wired and Wireless

University of Texas at Arlington CSE 5346/4346 High Performance Networks 5 NS Models Wired - Routing: DV, LS, PIM-SM etc. - Transportation: TCP and UDP - Traffic sources: web, ftp, telnet, cbr, stochastic etc. - Queuing disciplines: drop-tail, RED, FQ, SFQ, DRR etc. - QoS: IntServ and Diffserv … - Emulation Wireless - Ad hoc routing, mobile IP and Satellite - Directed diffusion, sensor-MAC

University of Texas at Arlington CSE 5346/4346 High Performance Networks 6 NS Architecture Object-oriented (C++, OTcl) 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

University of Texas at Arlington CSE 5346/4346 High Performance Networks 7 OTcl and C++: The Duality C++ otcl C++/OTcl split objects Pure C++ objects Pure OTcl objects ! OTcl (object variant of Tcl) and C++ share class hierarchy !

University of Texas at Arlington CSE 5346/4346 High Performance Networks 8 NS Components - visualize ns (or other) output Pre-processing: - Traffic and topology generators Post-processing: - simple trace analysis, often in Tcl, Awk or Perl

University of Texas at Arlington Part II: How to Run NS-2

University of Texas at Arlington CSE 5346/4346 High Performance Networks 10 How to Run NS-2 ① gamma2 server - Version: Please use /tmp for your trace files (not codes) (later) - xdisplay for graphical results ② If you want to install NS2 in your own PC - Current release: ns-2.31, Mar 10, 2007)  - Platforms  Most Unix and Linux  Windows and Mac

University of Texas at Arlington CSE 5346/4346 High Performance Networks 11 How to Setup Path ls –a.cshrc setenv LD_LIBRARY_PATH /opt/ns-allinone-2.30/….bash_profile export PATH=/opt/ns-allinone-2.30/bin:$PATH export LD_LIBRARY_PATH=/opt/ns-allinone-2.30/otcl- 1.12:/opt/ns-allinone-2.30/lib:$LD_LIBRARY_PATH export TCL_LIBRARY=/opt/ns-allinone- 2.30/tcl8.4.13/library

University of Texas at Arlington CSE 5346/4346 High Performance Networks 12 gamma /tmp for Temporary Usage only - Do Not save your scripts under /tmp Use Your Own directory - mkdir /tmp/your_dir/ Example set nf [open /tmp/your_dir/out.nam w]

University of Texas at Arlington CSE 5346/4346 High Performance Networks 13 How to Install NS-2 (Under Windows) m_Under_Windows_9x/2000/XP_Using_Cygwinhttp://nsnam.isi.edu/nsnam/index.php/Running_Ns_and_Na m_Under_Windows_9x/2000/XP_Using_Cygwin Cygwin or later required Select “UNIX” text type to check current mode, type “mount | grep textmode” C:\Cygwin (not C:\Program Files\Cygwin) “Install” and Categories (next page) and others (e.g., vim) in Download NS-2 under Cygwin (E.g., under /usr/local/) tar zxvf ns-allinone-2.2x.x.tar.gz cd ns-allinone-2.2x./install

University of Texas at Arlington CSE 5346/4346 High Performance Networks 14

University of Texas at Arlington CSE 5346/4346 High Performance Networks 15 Error? error near unexpected token `)'./configure: line 7624: ` OSF*)' tcl8.3.2 configuration failed! Exiting... Tcl is not part of the ns project. Please see to see if they have a fix for your platform. - Remove ‘ only if there are two ‘ at the end of relid - find. | xargs -n 1 grep -H relid\‘ Others - installing-ns-2292-allinone.htmlhttp://ns-2.blogspot.com/2006/05/problem-in- installing-ns-2292-allinone.html -

University of Texas at Arlington CSE 5346/4346 High Performance Networks 16 How to Use Cygwin-X Run /usr/X11R6/bin/startxwin.bat % sh /usr/X11R6/bin/startxwin.sh % cp /etc/X11/xinit/xinitrc ~/.xinitrc PATH=%PATH:/usr/X11R6/bin % startx &

University of Texas at Arlington CSE 5346/4346 High Performance Networks 17 NS-2 Directory Structure TK OTcltclcl Tcl ns-2nam-1.12 tcl extest lib... examples validation tests C++ code OTcl code ns-allinone mcast /opt/ns-allinone-2.30/...

University of Texas at Arlington Part III: How to Program

University of Texas at Arlington CSE 5346/4346 High Performance Networks 19 Basic Tcl Programming setb 0 - “b = 0” in C set x $b set x [expr $a + $b] sop.inria.fr/maestro/personnel/Eitan.Altman/COURS-NS/n3.pdf sop.inria.fr/maestro/personnel/Eitan.Altman/COURS-NS/n3.pdf

University of Texas at Arlington CSE 5346/4346 High Performance Networks 20 Basic Tcl # Command arg1 arg2 arg3 … set a 43 set b 27 proc test { a b } { set c [expr $a + $b] set d [expr [expr $a - $b] * $c] for {set k 0} {$k < 10} {incr k} { if {$k < 5} { puts “k < 5, pow = [expr pow($d, $k)]” } else { puts “k >= 5, mod = [expr $d % $k]” }

University of Texas at Arlington CSE 5346/4346 High Performance Networks 21 Elements of NS-2 Create the event scheduler [Turn on tracing] Create network Setup routing Insert errors Create transport connection Create traffic Transmit application-level data

University of Texas at Arlington CSE 5346/4346 High Performance Networks 22 How to Simulate Create event scheduler - set ns [new Simulator] Schedule events - $ns at  : any legitimate ns/tcl commands - $ns at 5.0 “finish” Start scheduler - $ns run TclCL - C++ and OTcl linkage - glue library that makes it easy to share functions, variables, etc NS-2 Tcl OTcl TclCL Event Scheduler Network Components C/C++

University of Texas at Arlington CSE 5346/4346 High Performance Networks 23 Example: helloWorld.tcl set ns [new Simulator] $ns at 1 “puts \“Hello World!\”” $ns at 1.5 “exit” $ns run % ns simple.tcl Hello World! %

University of Texas at Arlington CSE 5346/4346 High Performance Networks 24 Creating Network Nodes - set n0 [$ns node] - set n1 [$ns node] Links and queuing - $ns duplex-link $n0 $n1 - : DropTail, RED, CBQ, FQ, SFQ, DRR - $ns duplex-link-op $no $n1 OPTIONS n0n1

University of Texas at Arlington CSE 5346/4346 High Performance Networks 25 Setup Routing Unicast - $ns rtproto - : Static, Session, DV, cost, multi-path Multicast - $ns multicast (right after [new Simulator]) - $ns mrtproto - : CtrMcast, DM, ST, BST

University of Texas at Arlington CSE 5346/4346 High Performance Networks 26 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 n0n1 UDPnull

University of Texas at Arlington CSE 5346/4346 High Performance Networks 27 Creating Traffic: On Top of UDP CBR - set src [new Application/Traffic/CBR] - $src attach-agent $udp0 Exponential or Pareto on-off - set src [new Application/Traffic/Exponential] - set src [new Application/Traffic/Pareto] - $src attach-agent $udp0 n0n1 UDPnull CBR

University of Texas at Arlington CSE 5346/4346 High Performance Networks 28 Structure of a Unicast Node

University of Texas at Arlington CSE 5346/4346 High Performance Networks 29 Structure of a Simplex Link

University of Texas at Arlington CSE 5346/4346 High Performance Networks 30 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 n0n1 TCP sink

University of Texas at Arlington CSE 5346/4346 High Performance Networks 31 Creating Traffic: On Top of TCP FTP - set ftp [new Application/FTP] - $ftp attach-agent $tcp Telnet - set telnet [new Application/Telnet] - $telnet attach-agent $tcp n0n1 TCP sink FTP

University of Texas at Arlington CSE 5346/4346 High Performance Networks 32 A simulation example n0 n1 n2n3 n4 n5 tcp sink ftp 5Mb, 15ms 10Mb,2ms W=32

University of Texas at Arlington CSE 5346/4346 High Performance Networks 33 TCP Agents ns has several variants of TCP available: - -- Agent/TCP/Tahoe a ``tahoe'' TCP sender - -- Agent/TCP/Reno a ``Reno'' TCP sender - -- Agent/TCP/NewReno Reno with a modification - -- Agent/TCP/Sack1 TCP with selective repeat (follows RFC2018) - -- Agent/TCP/Vegas TCP Vegas - -- Agent/TCP/Fack Reno TCP with ``forward acknowledge ment'' The oneway TCP receiving agents currently supported are: - -- Agent/TCPSink TCP sink with one ACK per packet - -- Agent/TCPSink/DelAck TCP sink with configurable delay per ACK - -- Agent/TCPSink/Sack1 selective ACK sink (follows RFC2018) - -- Agent/TCPSink/Sack1/DelAck Sack1 with DelAck The twoway experimental sender currently supports only a Reno form of TCP: - -- Agent/TCP/FullTcp

University of Texas at Arlington CSE 5346/4346 High Performance Networks 34 TCP Agent Parameters Agent/TCP set tcpTick— 0.1 ;# timer granularity in sec (.1 is NONST ANDARD) Agent/TCP set maxrto— 64 ;# bound on RTO (seconds) Agent/TCP set dupacks— 0 ;# duplicate ACK counter Agent/TCP set ack— 0 ;# highest ACK received Agent/TCP set cwnd— 0 ;# congestion window (packets) Agent/TCP set awnd— 0 ;# averaged cwnd (experimental) Agent/TCP set ssthresh— 0 ;# slowstat threshold (packets) Agent/TCP set rtt— 0 ;# rtt sample Agent/TCP set srtt— 0 ;# smoothed (averaged) rtt Agent/TCP set rttvar— 0 ;# mean deviation of rtt samples Agent/TCP set backoff— 0 ;# current RTO backoff factor Agent/TCP set maxseq— 0 ;# max (packet) seq number sent

University of Texas at Arlington CSE 5346/4346 High Performance Networks 35 Tracing and Monitoring I Trace packets on all links #Open the NAM trace file #Open the Trace file - set nf [open out.nam w] set tf [open out.tr w] - $ns namtrace-all $nf $ns trace-all $tf Must appear immediately after creating scheduler Turn on tracing on specific links - $ns trace-queue $n0 $n1 - $ns namtrace-queue $n0 $n1 Event tracing (support TCP right now) - Record “event” in trace file: $ns eventtrace-all

University of Texas at Arlington CSE 5346/4346 High Performance Networks 36 Tracing and Monitoring II

University of Texas at Arlington CSE 5346/4346 High Performance Networks 37 Tracing and Monitoring III Queue monitor set qmon [$ns monitor-queue $n0 $n1 $q_f $sample_interval] - Get statistics for a queue $qmon set pdrops_ - Record to trace file as an optional Flow monitor set fmon [$ns_ makeflowmon Fid] $ns_ attach-fmon $slink $fmon $fmon set pdrops_

University of Texas at Arlington CSE 5346/4346 High Performance Networks 38 Tracing and Monitoring IV Variable tracing in nam Agent/TCP set nam_tracevar_ true $tcp tracevar srtt_ $tcp tracevar cwnd_ Monitor agent variables in nam $ns add-agent-trace $tcp $tcp $ns monitor-agent-trace $tcp $srm0 tracevar cwnd_ …… $ns delete-agent-trace $tcp

University of Texas at Arlington CSE 5346/4346 High Performance Networks 39 Visualization Tools nam-1 (Network AniMator Version 1) - Packet-level animation - Well supported by ns xgraph - Conversion from ns trace to xgraph format

University of Texas at Arlington CSE 5346/4346 High Performance Networks 40 xgraph The xgraph program draws a graph on an X display given data read from either data files. - To run it: xgraph dataFileName You can save the hardcopy of the graph as a postscript file. Xgraph is available on gamma : - /opt/ns-allinone-2.30/xgraph-12.1

University of Texas at Arlington CSE 5346/4346 High Performance Networks 41 nam Basic visualization - Topology layout - Animation control - Synchronous replay Fine-tune layout TCP/SRM visualization Editor: generate ns simulation scripts

University of Texas at Arlington CSE 5346/4346 High Performance Networks 42 ns  nam Interface Color Node manipulation Link manipulation Topology layout Protocol state Misc

University of Texas at Arlington CSE 5346/4346 High Performance Networks 43 nam Interface: Color Color mapping $ns color 1 red $ns color 2 blue $ns color 3 chocolate Color  flow id association $tcp0 set fid_ 1;# red packets $tcp1 set fid_ 2;# blue packets

University of Texas at Arlington CSE 5346/4346 High Performance Networks 44 nam Interface: Nodes Color $node color red Shape (can’t be changed after sim starts) $node shape box;# circle, box, hexagon Marks (concentric “shapes”) $ns at 1.0 “$n0 add-mark m0 blue box” $ns at 2.0 “$n0 delete-mark m0” Label (single string) $ns at 1.1 “$n0 label \”web cache 0\””

University of Texas at Arlington CSE 5346/4346 High Performance Networks 45 nam Interfaces: Links Color $ns duplex-link-op $n0 $n1 color "green" Label $ns duplex-link-op $n0 $n1 label "abced" Dynamics (automatically handled) $ns rtmodel Deterministic { } $n0 $n1 Asymmetric links not allowed

University of Texas at Arlington CSE 5346/4346 High Performance Networks 46 nam Interface: Topo 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

University of Texas at Arlington CSE 5346/4346 High Performance Networks 47 nam Interface: Protocol State Monitor values of agent variables $ns add-agent-trace $srm0 srm_agent0 $ns monitor-agent-trace $srm0 $srm0 tracevar C1_ $srm0 tracevar C2_ # … … $ns delete-agent-trace $tcp1

University of Texas at Arlington CSE 5346/4346 High Performance Networks 48 nam Interface: Misc Annotation - Add textual explaination to your sim $ns at 3.5 "$ns trace-annotate \“packet drop\"“ Set animation rate $ns at 0.0 "$ns set-animation-rate 0.1ms"

University of Texas at Arlington CSE 5346/4346 High Performance Networks 49

University of Texas at Arlington CSE 5346/4346 High Performance Networks 50 Summary: Generic Script Structure set ns [new Simulator] # [Turn on tracing] # Create topology # Setup packet loss, link dynamics # Create routing agents # Create: # - multicast groups # - protocol agents # - application and/or setup traffic sources # Post-processing procs # Start simulation