Book Image

GNS3 Network Simulation Guide

Book Image

GNS3 Network Simulation Guide

Overview of this book

GNS3 is an open-source Graphical Network Simulator used extensively by networking professionals to simulate networking devices such as Cisco, Juniper and Vyatta routers, along with Virtual PCs. GNS3 Network Simulation Guide gives you all the information you need to run a successful GNS3 simulation. You will be guided through the tricky installation pre-requisites and procedures involved in developing a simulated topology suitable for studying for Cisco CCIE Certification. We will also cover many useful tips and tricks which will help you make the most of your GNS3 simulator application. You will begin the GNS3 journey by ensuring that you have prepared your computer with any additional files required by GNS3, to set up the simulated environment needed for a successful installation process. Once GNS3 is installed, you will get to work creating a successful simulation including routers, Ethernet switches, Virtual PCs, and capture packets using Wireshark. Next, you will learn how to master GNS3's Graphical User Interface as well as the Command Console. The inner workings of GNS3 are described in depth so that you gain an appreciation of how UDP tunnels are used to tie the many components of GNS3 together. By following the clear examples and exercises in this guide, you will learn everything that you need to know about how to use GNS3 to prepare for certifications, as well as simulate real-world network scenarios.
Table of Contents (14 chapters)
GNS3 Network Simulation Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Understanding the topology.net file


By now you will have noticed that when you open a GNS3 project, you have to select a file with a .net extension, usually topology.net.

Firstly, understand that the topology file does not have to be called topology.net. But as GNS3 evolved, it became more practical to simply call the file topology.net, and since GNS3 v0.8.3 has only ever saved a new topology file as toplogy.net. You may find older topologies or even manually handcrafted files, usually with a .net extension that will open happily in GNS3.

In fact, the .net file format actually belongs to Dynagen, and you can take any .net file produced by GNS3 and use it directly with Dynagen independently of GNS3. To get a full understanding of the sections of the file that both GNS3 and Dynagen use and interpret, see Greg Anuzelli's tutorial available at: http://dynagen.org/tutorial.htm, but here is a brief overview.

The topology.net file created by GNS3 has two parts. Here is a sample:

autostart = False
version...