What is GNS3? | What does GNS3 do?GNS3 is a Graphical Network Simulator that allows you to design complex networks by emulating network devices such as Cisco Routers / Switches. GNS3 is Open Source software which can be downloaded and used for free.
What is GNS3? | What does GNS3 do?

What is GNS3? | What does GNS3 do?

With GNS3 you can work better on Cisco exams by creating complex network designs on your computer. In the GNS3 infrastructure, a program called Dynamips runs and allows you to run real Cisco IOS images in a virtual environment. The GNS3 network simulator program can be installed on Windows, Mac OS X, Linux, Unix, FreeBSD operating systems.

Christophe Fillot is the founder of the Dynamips (MIPS Processor Emulation Program) program, which enables network devices such as the Cisco Router to run in the virtual environment. The founder of Dynamips is Grossman.

Using the GNS3 network simulator, you can work more effectively for Cisco exams such as Cisco Certified Network Associate (CCNA) and Cisco Certified Network Professional (CCNP).

GNS3 does not only support Cisco devices, but also Juniper, MikroTik, Arista and Vyatta network devices.

Instead of using GNS3, you can also use the Cisco Packet Tracer program developed by Cisco Networking Academy. For more information about the Cisco Packet Tracer, you can check out What is Cisco Packet Tracer.

What is GNS3 used for?

You can use Cisco IOS images with back-end Hypervisor software more specifically through this network simulator program compared to other network simulator programs (RouterSim, Boson NetSim) on GNS3. Other network simulator programs include their network devices such as Router or Switch. As a result, with GNS3 you can run and use a real Cisco Router on your computer.

After creating simple or complex network designs using GNS3, you can add and use Router, Switch or Firewall (Cisco ASA) in the workspace.

What is GNS3? | What does GNS3 do?

A Cisco Router or Cisco Switch running on GNS3 uses IDLE-PC Value to ensure that your computer does not consume too much hardware resources. You can configure IDLE-PC for a Cisco Router after you add a new device.

When setting IDLE-PC value for a network device on GNS3, the value with the symbol ( * ) will be the best value provided by your system.

GNS3 Network Simulator Components

GNS3 → GUI (Graphical User Interface) for Dynamips.
Dynamips → Emulator for IOS.
Dynagen → Startup Stage for Dynamips Front End.
Pemu → Based on Qemu Cisco PIX Firewall Emulator.
(Win)Pcap → Package Capture Library | Driver for Sniffer (Monitoring).
Wireshark (Formerly Ethereal) → Network Monitoring / Listening to the Network.
VPCS → Virtual PCs (Virtual Computer) → Adding a virtual computer to the program without adding a virtual computer to GNS3.
VMware VMS → VMware Virtual Machines → Including the virtual machines on VMware Workstation to the GNS3.
VirtualBox VMS → VirtualBox Virtual Machines → Including the virtual machines on VirtualBox to the GNS3.
IOU Devices → It provides you with all the features of a network device by adding a true Layer 2 and Layer 3 Switch IOS image to GNS3.

GNS3 Advantages

After briefly mentioning about what is GNS3, let’s list the advantages of GNS3 for Cisco exams.

  1. Free software
  2. Open Source software
  3. There is no monthly or annual license fee
  4. There is no limit to the number of supported devices (only the limiting hardware: CPU and memory)
  5. Supports multiple switching options (ESW16 Etherswitch, IOU / IOL Layer 2 displays, VIRL IOSvL2):
  6. Supports all VIRL images (IOSv, IOSvL2, IOS-XRv, CSR1000v, NX-OSv, ASAv)
  7. Supports many brands of devices
  8. Can run without hypervisor
  9. It supports both free and paid hypervisors (Virtualbox, VMware Workstation, VMware Player, ESXi, Fusion)
  10. Downloadable, free, preconfigured and optimized devices to simplify deployment
  11. Local support for Linux without the need for additional virtualization software
  12. Software from multiple vendors is freely available
  13. Large and active community (more than 800,000 members)

GNS3 Disadvantages

  1. Cisco IOS images need to be supplied by the user (download from Cisco.com, or purchase VIRL license, or copy from the physical device).
  2. Not a self-contained package but requires a local installation of software (GUI).
  3. GNS3 can be affected by your PC’s setup and limitations because of local installation (firewall and security settings, company laptop policies etc).

How to Install GNS3 on Windows Operating System? ⇒ Video

To better understand what is GNS3, you can watch the video below to install GNS3 step by step. Also, you can subscribe to our YouTube channel to support us…

How to Install and Use GNS3 on Linux Systems?

As mentioned above, you can also install the GNS3 network simulator program on Linux systems (such as Ubuntu, Debian, Linux Mint). For example, to install GNS3 on Ubuntu 17.10, you can click on the image below to browse the related article.

What is GNS3? | What does GNS3 do?

How to Install GNS3 on Mac Computers?

You can also run GNS3 on Mac computers. To setup GNS3 on operating systems such as MacOS Sierra / MacOS High Sierra, you can view the related article by clicking on the image below.

What is GNS3? | What does GNS3 do?

  Final Word

What is GNS3? | What does GNS3 do? – You can use the GNS3 network simulator program instead of purchasing network devices like the Cisco Router to prepare for the Cisco exams or improve yourself. In addition, you can access all configuration commands that are not supported in Cisco Packet Tracer using the real Router’s image files on GNS3. Thanks for following us!

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