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

Say hello to the hypervisor


When Christophe Fillot began emulating Cisco routers with Dynamips, each instance of a simulated router required its own instance of Dynamips, along with a string of command line options to specify, for example, the amount of RAM, the interfaces, and the virtual connections to other instances of Dynamips. This soon gave way to an improved user interface using a hypervisor approach where a single instance of Dynamips could be initiated which accepted commands over a TCP pipe, usually on port 7200, so chosen because the Cisco 7200 was the first router to be emulated.

For a bit of fun, why not check out the Dynamips hypervisor yourself. From a command line, start Dynamips as a hypervisor running on port 7200 using the command:

dynamips –H 7200

Now start a telnet session to your localhost IP on port 7200:

telnet 127.0.0.1 7200

And finally issue a command Dynamips understands — the command ethsw create SW1 creates an instance of a generic switch. You should see a reply...