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

Cisco routers – emulated hardware


Dynamips supports a limited number of Cisco routers: Cisco 1700, 2600, 3600, 3700, and 7200 routers to be precise. These routers were designed with generic off-the-shelf processors with well-known published specifications, so Christophe Fillot (the author of Dynamips) was able to write software to emulate these well-known functions well enough to interpret the instruction set from a Cisco IOS image for the precedingly mentioned routers and execute it.

Modern Cisco routers use proprietary ASICs to perform switching, so no one outside of Cisco knows what the functions are. Emulation of these devices is impossible without reverse engineering or otherwise obtaining Cisco's intellectual property.

So that's the way it is for Dynamips. It may not be the end of the story though for GNS3, because GNS3 supports other emulators as well. When Cisco start releasing more routers as Virtual Machines (like Vyatta does) it may be possible that these routers will be able to...