Скачать презентацию Tutorial on Network Simulator NS 2 Hemant Kumar Скачать презентацию Tutorial on Network Simulator NS 2 Hemant Kumar

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Tutorial on Network Simulator (NS 2) Hemant Kumar Rath Infonet Lab, Dept of Electrical Tutorial on Network Simulator (NS 2) Hemant Kumar Rath Infonet Lab, Dept of Electrical Engineering IIT Bombay, Mumbai - 400076 Network Simulator (NS 2) 1

Introduction Ø Discrete event simulator targeted at networking research and education v Protocol design, Introduction Ø Discrete event simulator targeted at networking research and education v Protocol design, traffic studies, etc v Protocol comparison v Wired and wireless networks Ø Back end is in C++ and front end is in o. Tcl Ø Provide a collaborative environment v Open source, Freely distributed • Share code, protocols, models, etc • No code guarantee v Easy comparison of similar protocols Network Simulator (NS 2) 2

Simulation Network Ø Wired Network v Routing: Distance Vector, Link State v Transportation: TCP Simulation Network Ø Wired Network v Routing: Distance Vector, Link State v Transportation: TCP and UDP v Queuing disciplines: drop-tail, RED, FQ, SFQ, DRR, RR v Qo. S: Int. Serv and Diff. Serv Ø Wireless v Ad-hoc routing and mobile IP: AODV v Sensor-MAC, Wi. MAX (new) v Power control in wireless networks Ø Tracing, Visualization, Analysis, Other utilities Network Simulator (NS 2) 3

NS 2 Functionalities Ø Traffic models and applications v Web, FTP, Telnet, CBR, real NS 2 Functionalities Ø Traffic models and applications v Web, FTP, Telnet, CBR, real time traffic Ø Transport protocols v Unicast: TCP (Reno, New-Reno, Vegas, etc. ), UDP v Multicast: SRM Ø Routing and queuing v Wired and ad-hoc routing and directed diffusion v Queuing protocols: RED, drop-tail, etc Ø Physical media v Wired (point-to-point, LANs), wireless (multiple propagation models), error models, satellite Network Simulator (NS 2) 4

How to work in NS 2 ? Ø Download the software Ø Install NS How to work in NS 2 ? Ø Download the software Ø Install NS 2 in your home directory v Compile the latest version of NS 2 v Validate NS 2 Ø Create your topology v Need to understand the real topology and the directory structure in NS 2 v Modify the existing codes • C++ and/or. tcl files v Create your own. tcl script for this Ø Execute the script v Analyze your result Network Simulator (NS 2) 5

Download and Installation of NS 2 Ø Select the Operating System v NS 2 Download and Installation of NS 2 Ø Select the Operating System v NS 2 is available for both Windows and Linux v Linux is desirable as C++ compiler is free and easy to debug Ø Check your Hardware v Processor speed, RAM, home directory space • Minimum 400 MB space is required Ø Download the appropriate source file v Available locally in the course home page • http: //sharada. iitb. ac. in/~ee 706/ns 2. html v Read the instructions in details before installation Network Simulator (NS 2) 6

Download and Installation of NS 2 Ø Install NS 2 in your home directory Download and Installation of NS 2 Ø Install NS 2 in your home directory v Follow the instructions given in the course home page v For trouble shooting refer to the links provided in the course home page • http: //nsnam. isi. edu/nsnam/index. php/Troubleshooting v Else, do a google search Ø Solutions to most of the problems are available in the NS 2 mailing list v http: //www. isi. edu/nsnam/ns/ns-lists. html Network Simulator (NS 2) 7

Create your Topology Ø Decide what do you want to simulate v Wired or Create your Topology Ø Decide what do you want to simulate v Wired or wireless network v What are the protocols? v How many nodes, what are the measuring parameters? v What are the applications involved, etc? Ø Make a rough sketch of the topology v Figure out the concerned files (C++ or. tcl) v Based on the requirement do the following • Edit the existing C++ files and/or the. tcl files • You can create new C++ files Network Simulator (NS 2) 8

Data and Control Separation Ø o. TCL in the Front End v Control part Data and Control Separation Ø o. TCL in the Front End v Control part of NS 2 v Topology (Simulation scenario) configurations v Event driven • Periodic or Triggered action v Manipulates existing C++ objects v Easy to write and edit Ø C++ in the Back End v Core of NS 2, data part of NS 2 v Easy to modify the code • Not fully layered and structured v Packet processing and execution Network Simulator (NS 2) 9

Directory Structure Ø Main directories v bin, ns-2 xx, lib, man, include, etc in Directory Structure Ø Main directories v bin, ns-2 xx, lib, man, include, etc in ns 2 home Ø ns-2. xx v Readme file v Makefile, installation file, tutorial, etc v Source files related to the protocols • All. cpp and. h files related needed for editing v Need understanding of interaction among the functions/sub routines v Not fully layered like Qual. Network Simulator (NS 2) 10

Compiling NS 2 Ø Create / Modify the C++ file v If you are Compiling NS 2 Ø Create / Modify the C++ file v If you are creating new C++ file, include the name of the new files in the Makefile v If you are editing the existing C++ files, keep a copy of the original file v Add comments to your modifications with date Ø Compile NS 2 v After creation/editing, compile NS 2 using • (make clean; ) make; • Check for errors, if any and rectify Network Simulator (NS 2) 11

Executing NS 2 Ø Create your. tcl script as per your topology Ø Run Executing NS 2 Ø Create your. tcl script as per your topology Ø Run the. tcl file using ns command v Check which ns 2 you are using v Create a huge output file (trace file) to analyze v Need to understand the file contents v Perl scripts are also available to analyze the trace file Ø Analyze using nam v Visual network animator Ø Single thread of control v No locking or race conditions to worry about Network Simulator (NS 2) 12

Functional Diagram of NS 2 Problem Result Analysis/debug Topology Modify ns (. cpp/. tcl) Functional Diagram of NS 2 Problem Result Analysis/debug Topology Modify ns (. cpp/. tcl) Setup/execute simulation with ns (. tcl) Network Simulator (NS 2) 13

Simulation with NS 2 Ø Create a New Event Scheduler (simulator env. ) Ø Simulation with NS 2 Ø Create a New Event Scheduler (simulator env. ) Ø Turn on Tracing v Can use nam also Ø Topology Creation v Create Nodes, Network, Queuing, etc. v Setup Routing v Send Data • Create Transport Connection, Create Traffic, Start Applications v Insert Errors Ø Analyze the Trace File Network Simulator (NS 2) 14

Event Scheduler Ø Event v Generation of a packet, start/finish of transmission Ø Create Event Scheduler Ø Event v Generation of a packet, start/finish of transmission Ø Create a New Event Scheduler set ns [new Simulator] Ø Schedule Events $ns at

Tracing and Analyzing Ø Packet Tracing v On all links • $ns trace-all [open Tracing and Analyzing Ø Packet Tracing v On all links • $ns trace-all [open cwnd. tr w] v On one specific link • $ns trace-queue $n 0 $n 1$tr

Topology Creation Ø Create Nodes v set n 0 [$ns node] v set n Topology Creation Ø Create Nodes v set n 0 [$ns node] v set n 1 [$ns node] Ø Assign Links and Queuing v $ns $n 0 $n 1 : duplex-link, simplex-link • : Drop. Tail, RED, CBQ, FQ, SFQ, DRR, diffserv RED queues • Viz: $ns duplexlink $n 0 $n 1 1 Mb 10 ms Drop. Tail § Link between n 0 and n 1 is duplex, 1 Mbps capacity, 10 msec delay and queue is Drop Tail Network Simulator (NS 2) 17

Setup Routing Ø Unicast v $ns rtproto <type> • <type>: Static, Session, DV, cost, Setup Routing Ø Unicast v $ns rtproto : Static, Session, DV, cost, multi-path Ø Multicast v $ns multicast (right after [new Simulator]) v $ns mrtproto : Ctr. Mcast, DM, ST, BST Ø Other Types of Routing Supported v Source routing, Hierarchical routing Network Simulator (NS 2) 18

Sending Data Ø Create UDP Agent and Attach v set udp 0 [new Agent/UDP] Sending Data Ø Create UDP Agent and Attach v set udp 0 [new Agent/UDP] v $ns attach-agent $n 0 $udp 0 Ø Create CBR Traffic v set src [new Application/Traffic/CBR] • set cbr 0 [new Application/Traffic/CBR] • $cbr 0 set packet. Size_ 500 • $cbr 0 set interval_ 0. 005 • $cbr 0 attachagent $udp 0 Ø Create Traffic Sink and Attach v set null [new Agent/Null] v $ns attach-agent $n 1 $null Network Simulator (NS 2) 19

Sending Data Ø Create Exponential or Pareto on-off v set src [new Application/Traffic/Exponential] v Sending Data Ø Create Exponential or Pareto on-off v set src [new Application/Traffic/Exponential] v set src [new Application/Traffic/Pareto Ø Connect two Agents v $ns connect $udp 0 $null Ø Start and Stop of Data v $ns at 0. 5 “$cbr 0 start” v $ns at 4. 5 “$cbr 0 stop” Ø Create TCP Agent and Attach v set tcp 0 [new Agent/TCP] v $ns attach-agent $n 0 $tcp 0 Network Simulator (NS 2) 20

Sending Data Ø Create Traffic Sink and Attach v set null 0 [new Agent/TCPSink] Sending Data Ø Create Traffic Sink and Attach v set null 0 [new Agent/TCPSink] v $ns attach-agent $n 1 $null 0 Ø Connect the Agents v $ns connect $tcp 0 $null 0 Ø Traffic on Top of TCP v FTP • set ftp [new Application/FTP] • $ftp attach-agent $tcp 0 v Telnet • set telnet [new Application/Telnet] • $telnet attach-agent $tcp 0 Network Simulator (NS 2) 21

Inserting Errors Ø Creating Error Module v set loss_module [new Error. Model] v $loss_module Inserting Errors Ø Creating Error Module v set loss_module [new Error. Model] v $loss_module set rate_ 0. 01 v $loss_module unit pkt v $loss_module ranvar [new Random. Variable/Uniform] v $loss_module drop-target [new Agent/Null] Ø Inserting Error Module v $ns lossmodel $loss_module $n 0 $n 1 Network Simulator (NS 2) 22

Analyze the Trace File Ø Trace files are huge in size v Only redirect Analyze the Trace File Ø Trace files are huge in size v Only redirect the parameters you want to measure v Traces begin with a single character or abbreviation v It indicates the type of trace, followed by a fixed or variable trace format Ø Perl scripts are available to analyze trace files Ø Refer for the details v http: //nsnam. isi. edu/nsnam/index. php/NS-2_Trace_Formats Network Simulator (NS 2) 23

Queries? hemantr@ee. iitb. ac. in Network Simulator (NS 2) 24 Queries? [email protected] iitb. ac. in Network Simulator (NS 2) 24