Computer Network Simulation in NS2

Basic Concepts and Protocols Implementation

Neeraj Bhargava, Pramod Singh Rathore, Dr. Ritu Bhargava, Dr. Abhishek Kumar, Neeraj Bhargava

• Publisher: BPB Publications
• Year: 2019
• eBook ISBN: 9789388511827
• Topic: Computer Science
• Subtopic: Computer Science General
• Index: Computer Science

Learn to design the Mobile Ad-hoc Networks Key Features

• Installing NS2 and running simple examples
• Creating and incorporating the network module
• All the built-in NS2 modules are explained in a comprehensive manner
• Details of Network AniMator (NAM) and Xgraph
• Simple language, crystal clear approach, and a straightforward comprehensible presentation
• The concepts are duly supported by several examples
• 
  Description
  Network Simulation is the most sought after research field, and it has now become an integral part of many research projects like commercial applications and academic research. The networking and communications domain ranges from finding friends on social networking sites to medical diagnosis to smart cities implementation and even satellite processing. In this book, we have made an honest effort to make the concepts of network simulation easy—all the basics programs are explained in an easy and simple manner in the NS2 simulator, right from the installation part. As the real-time application of networking and communications is endless, the basic concepts and algorithms are discussed using the NS2 simulator so that everyone—from graduate students to researchers—can benefit from this book. What You Will Learn
  Readers will get to know a conspicuous difference of how NS2 is being utilized as a product device in research and business applications. Today, applying network simulations does not require a PhD. Nonetheless, there are a couple of assets out there that completely cover all the essential parts of actualizing networking and communications, without expecting you to take the advanced math courses. We believe that this book will help any individual who needs to apply network simulation, without studying years of analytics, calculus math, and probability hypothesis. Who this book is for
  The book is basically meant for all those graduate and research students who find the algorithms and protocols of networking and communications difficult to implement. In this book, all basic protocols of networking and simulation are discussed in detail with a practical approach. Primarily, beginners can find this book more effective as the chapters are sub-divided in such a way that they will find building and implementing algorithms in NS2 interesting and easy. Table of Contents
  1. Introduction to Network Simulation
  2. Tool Command Language
  3. Writing and Executing a TCL Scripting with NS2
  4. Practical Examples for Wired Program in NS2
  5. Mobile Networking in NS2 About the Author
  Professor Neeraj Bhargava has done his B.Tech in computer science from the Central University of Hyderabad, India and M.S. in computer science from BITS Pillani, India, and has also completed his PhD in computer science from the University of Rajasthan, Jaipur, India. Pramod Singh Rathore is pursuing his doctorate in computer science and holds a degree in M. Tech in computer science and engineering from Rajasthan Technical University, a government engineering college in Kota, Ajmer. Dr Ritu Bhargava is an assistant professor at the Department of Computer Science, Sophia Girls College, Ajmer. She holds a PhD in computer science from Hemchandracharya North Gujarat University, Patan, Gujarat. She also has more than 15 years of active teaching and research experience and has delivered a series of talks and lectures at reputed universities of India. Abhishek Kumar is holds a doctorate in computer science from the University of Madras and has done his M.Tech in computer science and engineering from Rajasthan Technical University, a government engineering college in Kota, Ajmer.
  

CHAPTER 1

Introduction to Network Simulation

Network simulation is not just a concept but it’s a real time application and practically oriented notion. The book primarily focuses on the basic practical approach to make Network simulation a lucid learning stream for readers. The basic notion behind compiling this book is to make students and scholar familiar with the fundamental details of network simulation concepts.

If you want to do or learn the concept of networking, then you should do a demo and make a small network and learn from it (how it behaves and what happens at each stage). Constructing a small network is quite expensive, apart from this you can do Simulation on internet.

• Simulations: It is a software which performs a task.
• Network Simulator 2: This is a version for solving a task. There are various versions available in market such as: ns1, ns2, ns3.

Network

Network allows computers to exchange data. Networking in the computer domain includes network simulator, networked devices to exchange data with each other via data connection (wired or wireless media). The optimal example of the networking in computer domain is the Internet.

The networking in computer domain can be defined as a collection of computers which are interconnected to each other and are used for gathering, processing, and distributing information. Networking includes workstation, the network simulator, servers, routers, modems, base station, wireless points, and so on. Computers transfer data through network simulator links such as copper cables, fibre optic cables, and microwave/satellite/radio links.

Network Simulator

The simulator used in networking is hardware or software which predicts the behavior of the networking in computer domain without actual network being present. In the different simulators, the networking in computer domain is typically modelled with devices, dynamic nodes, traffic between; with these parameters the performance of network simulator is analyzed. Users can model the simulator in order to fulfil their specific needs. Simulator used in networking is a combination of tools which simulates the pattern of networking scenario such as creating the networking topologies, log events which happen under any simulation, analyze the events and understand if the simulators is applicable in networking typically come with support for the most popular protocols and networks we use today, such as Wi-Max, WLAN, WSN, cognitive radio, TCP, and so on.

Overview

Network Simulation 2 is an event-driven simulator that simulates various kinds of IP networks. It implements network protocols such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP),File Transfer Protocol (FTP), Telnet, Web, Constant Bit Rate (CBR) and Variable Bit Rate (VBR), queue management methods such as Drop Tail, RED and CBQ, and some routing algorithm. Network Simulation 2also works with multicasting network-oriented programs and some of the Medium Access Control (MAC) layer protocols for local area network simulations. Network Simulation project is currently working for the VINT project which introduce tools for simulation results display, analysis, and converters which convert network topologies generated by the well-known generators to NS formats. At present, Network Simulation (version 2) is developed in C++ and OTcl. This book discusses briefly about the basic construction of NS and explains in detail how to use of NS frequently by giving examples.

As shown in figure 1.1, Network simulation is an Object-oriented tool script interpreted with simulation event scheduler, with the libraries of network component object, and with the libraries of network setup (plumbing) module (it is the plumbing modules which is implemented as member functions of the base simulator object). To use NS, we have to do programming in OTcl script language.

To create and run a simulation, OTcl script should be written by the user which creates an event, initiate the network topology, set up the objects of the network, comment the traffic sources, fix the transmission time and the stop time of transmitting packets through the event scheduler.

Figure 1.1: Simplified User’s View of NS

One more important component of NS beside network objects is the event scheduler. An event in NS is a packet ID which is unique for every packet with the unique scheduled time and the pointer to an object that handles the event. In NS, an event scheduler continuously tracks the simulation time period and fires all the simulation events in the event queue which is programmed for the present time by invoking suitable network components, not are the ones which issued the events in the simulation, and let them to perform the suitable action connected with packet pointed by the event.

Network components communicates with transitory packet; however, this does not devour real simulation time. Each network components spend a little simulation time for handling a packet with an essential delay uses event scheduler by providing an event for the packet. Consider an example, a network switch component which handles the simulation with 20 microseconds of switching delay issues an event for a data packet to be switched to the scheduler as an event 20 microsecond afterward. The scheduler following 20 microseconds handle the process of dequeue the event and fires it to the switch component, which subsequently send the packet to a suitable output link component.

Other control of event scheduler is timer. For example, Transmission Control Protocol (TCP) needs to make the use of a timer to track the transmission time of a packet out for the further transmission (transmission of a packet with the similar TCP packet number but dissimilar network packet identification). Timer measures a time linked with a packet and does a suitable action connected to that packet after a firm time goes by and does not simulate a time delay.

Why TCL

When you write an OTcl script which initiates an event scheduler and devices up the topology parameter of networking by using the item of network and the plumbing feature of the network simulator in the library, and then tells net web page, net page traffics assets. It is done to begin and prevent tracking of the network simulator transmitting packets through the event scheduler. The term “plumbing” is used for a network setup, because of the fact of installing a network is a plumbing viable records paths among an item of the network as the same way of setting the “neighbor” pointer of an item to cope up with the correct item. If a consumer wants to make a brand new network object, she or he may be capable of the consequences that may come while making an object each with the resource of the manner of writing a current item or through the manner of making a compound object from the object library, and plumb the records course through the object. This may seem to be a complex mission, but the plumbing OTcl modules, make the method very clean. The power of the network simulator comes from this plumbing.

The network simulators are no longer written in OTcl, but they are written in C++ additionally. For the overall performance purpose, the network simulator separates the statistics route implementation from the manage path implementation and the network simulator. So, in order to lessen the packet and event processing time (not the simulation time), the occasion scheduler and the fundamental components of object of networking the records direction are written and are compiled in C++. The one compiled...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Dedication
• About the Authors
• Acknowledgement
• Preface
• Errata
• Table of Contents
• 1. Introduction to Network Simulation
• 2. Tool Command Language
• 3. Writing and Executing a TCL Scripting with NS2
• 4. Practical Examples for Wired Program in NS2
• 5. Mobile Networking in NS2