GNS3


 * GNS3 **

GNS3 is an open source software which provides an intuitive graphical user interface to design and configure virtual networks. It runs on operating systems such as Windows, Linux, and MacOS X. GNS3 simulates running networks and devices such as routers, pcs,and switches. In order to run GNS3, three emulators are built into the program:
 * Description **

Dynamips: Cisco IOS emulator VirtualBox: Desktop and server OS emulator, including Juniper JunOS Qemu: Generic open source emulator which runs Cisco Asa, PIX, and IPS

It is so close to designing a network. It even utilizes the actual IOS from routers and switches. This is an open source product. Cisco Packet Tracer is the proprietary version.

The history of GNS3 really started with the creation of Dynamips by Christophe Fillot in 2005. It emulated a running Cisco router from a pc. The pitfall was that the CPU utilization was at 100%. On top of that, you needed two instances running in order to create a network. Quite impossible with the CPU running at 100%. In 2006, Dynamips was able to run in “hypervisor”mode which allowed multiple routers to be run in at one time. “Hypervisor” is similar to running a virtual machine on your pc and it is possible to run several instances. In addition, Greg Anuzelli gave the command line program a user interface called Dynagen. While this was an improvement, there still were problems maintaining the configuration files. Enter Jeremy Grossmn and Xavier Alt in 2007. With the combined efforts of the team, GNS3 was released. It was a nice package with icons that you could drag and drop simulating the routers. The configuration files had been upgraded such that it would remember your project. Mirnshi contributed the simulated pcs. Since then GNS3 has constantly improved with each revision. It is best run on a Linux platform in a virtual setting.
 * History **

GNS3 is an excellent alternative to real world networks. Its simulation is so close to designing and running a network. It is an excellent troubleshooting tool for those already in the field and a invaluable tool for beginners. It covers IOS such Cisco and Juniper. It is a must have for those studying for certifications at all levels.
 * Impact of Teaching and Learning **

Engineers and administrators love this tool. They can use it to test new application, configurations, or upgrades before deployment. It can be used to design a network and test it prior to implementation. The program even supports connectivity from the virtual scenario to the real one. You can use Wireshark, a packet tracer within the program to see the transmitted packets in real time. Furthermore, since the program is open source, it can be modified to suit your needs such as creating network tests.
 * Practical Applications **


 * Examples or Demonstrations **

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[] [] [] **  External Links   ** [|http://www.wireshark.org] [] [] [] [] **  About the Author   ** GNS3 has a whole team of developers and contributors. See the list at [] Redmine is built and maintained by community volunteers RedNectar's author is Chris Welsh, a professional computer networking instructor – Cisco, TCP/IP, VoIP
 * References  **