What is GNS3 (Graphical Network Simulator-3)?

The GNS3 (Graphical Network Simulator-3) software is a tool that allows you to simulate well-known network devices in the market virtually, such as Cisco Router, Switch, or Firewall.

This simulation tool lets you perform complex network setups on your PC.

What is the Importance of GNS3 for Network Simulation?

Because technology is growing a lot, there’s a significant need for people who know about information technology. This means that jobs in this field are becoming more and more critical.

A critical part of this is setting up and fixing computer networks for companies, whether they’re close by or far away. To help with this, computer programs like GNS3 let you practice using expensive network equipment on a computer instead of using the real thing.

As I said before, some network devices are cost, and not everyone can afford them. So, people can emulate and use them on their computers without paying anything.

Now, there’s a free software called GNS3 that you can use. Your computer should be strong and have a new kind of processor to do virtualization to use it.

GNS3 is essential for networks because it helps you make complicated networks. You can also add virtual machines and make them talk to each other. That’s why people who work with networks and students who are getting ready for tests, like the Cisco one, use GNS3.

What Does GNS3 Do?

GNS3 is a network simulation program that mimics different manufacturers’ network devices. It copies devices from various brands, so you can pretend to use them on your computer. This way, you can try out appliances that might be too expensive.

There are a few devices you can pretend to use, like:

• Virtual Router
• Virtual Switch
• Virtual Firewall

You can play around with both easy and tricky network devices.

So, you can test all kinds of devices without sticking to one brand’s products.

Also, GNS3 is good at running Cisco IOS images, much better than software like RouterSim or Boson NetSim. GNS3 does this by working closely with special back-end software called a hypervisor.

Simply put, GNS3 lets you use a genuine Cisco Router on your computer. It works smoothly by using an IDLE-PC value, which helps prevent your computer’s processor from getting too busy. This way, you can ensure a Cisco Router or Switch works appropriately.

Who Uses Network Simulation Software?

Indeed, when it comes to making PC networks, GNS3 is the most popular tool. Users aiming to enhance their fundamental network knowledge make use of it.

Also, many colleges and training centers use this software a lot. That’s because it lets people understand how a real network looks and works.

Moreover, they can make virtual PCs by adding VMs or VPCS devices. So, they can enhance their network experience by looking at IP packets on end-user PCs.

In simple terms, schools, training places, and courses use this fantastic PC program to learn about networks.

GNS3 History and Development

A person named Christophe Fillot made the Dynamips program in 2005. This program lets you use Cisco devices on a computer instead of the real thing. This idea later became GNS3, a program that enables you to work with virtual appliances on your PC.

GNS3, an essential PC program for networks, was started in 2007. If we look at the timeline, we can see that Jeremy Grossmann created this project as a free and open source.

When it first came out, this program only worked with Cisco Router devices, and it used something called Dynamips to pretend to be them. Initially, it looked simple and was easy for people to use. The fact that it works with Cisco devices and is easy to use is why many people like it today.

It’s worth mentioning that many people who like this program have helped it get even better. The software got updated and improved to work with more network devices as time passed.

This program has choices like VirtualBox, VMware, and QEMU. Because of these options, Cisco started to work with other companies’ Cisco products.

Later on, they added new things like Docker to make it better. This lets people include applications stored in containers in their network plans.

Thanks to features providing user support like these, it became popular worldwide. Also, the people who make the program constantly add and improve new things.

In the end, when we check out the story of GNS3, we’re happy about how it all came together and think it’s great.

What are the Basic Features of GNS3?

1. Dynamips Integration

A cool thing that’s been a part of GNS3 from the start is the use of Dynamips software, and it’s still used in GNS3 today. This lets users try out Cisco IOS images on their computers in a pretend world.

2. VirtualBox and VMware Support

The emulation program works with VMware’s Workstation and Oracle’s VirtualBox. Because of this, users can add various OS as guest machines to it.

3. QEMU Support

If you want to run non-Cisco devices, this feature is perfect! Thanks to QEMU, you can have a broader range of network devices. Additionally, you can use more advanced IOS images virtually on your PC through this.

4. Cisco Network Devices

So, the users who designed this program designed it to work with Cisco products. But now, it can also handle the advanced-level ones.

5. Non-Cisco Network Devices

The QEMU feature lets you use network devices from other companies like Juniper Junos, MikroTik, Arista, or Vyatta. In this case, you should also learn how to set up devices from different vendors.

6. Wireshark Packet Analysis

GNS3 makes it easy to look at IP packets when you use it with Wireshark. In simple terms, people can check how data moves around in extensive network topologies.

7. Solarwinds and Others

The graphical network simulator program also works with things like SolarWinds software and others. Because of this, people can bring in the software they use in real life and use it in the virtual program.

Other Great Features

1. Docker Integration

With the Docker feature, you can add container apps to your network projects. Plus, you can mix in services like private databases or web servers.

2. Python API

The Python API lets you use the network simulator with code. As a result, you can write a script and automatically make the computer do different tasks.

3. Snapshot

With the Snapshot feature, you can save your network’s current appearance. Later, imagine you are conducting tests by adding different elements to the current configuration. In this case, you can quickly revert to the previous state with a snapshot.

4. Cloud-Based Distributions

With the Cloud feature, you can bring your projects from faraway servers into your local software. So, it’s great for people who want to learn how cloud-based systems work.

What are the Advantages and Disadvantages of GNS3?

Pros

• Real Network Scenario

GNS3 is cool because it lets you use real network apps on your PC in a virtual emulation environment. Specifically, this helps people learn more about networks or try out new stuff.

• Various Device Support

In a real network, you usually have devices from different companies. So, it’s essential to set up each one correctly. This way, you can practice setting up other appliances and improve.

• Cost-Effective Solution

It’s a money-saving way to learn and study without buying real network devices. Therefore, people can practice and improve things in a virtual environment.

• Real Device Experience

It emulates a Cisco Router running on a physical network, giving you a setup that feels real. If you know how to use the Command Line Interface (CLI) on an actual device, you can do the same on this pretend one.

• Flexibility in Network Design

If you want to improve your current network setup, you can recreate it in the working environment. Then, you can try out different configurations and use the best one when you’re ready to change the real network.

• Collaboration

It helps many people work together on the same project in a school or learning place. This makes it easier for everyone to help each other and figure things out.

Cons

• Excessive Resource Consumption

It needs a lot of PC power when emulating Cisco or other vendor devices. For instance, if you’re adding many routers for an extensive complex network, you need a newer, more robust computer processor (CPU) and more memory (RAM).

• Network Information Requirement

When you use GNS3, you should already know a lot about networks. Therefore, you must understand how to connect network devices correctly, like linking two Cisco routers.

• Device Restrictions

While emulating specific devices, it may not fully support all features. So, it has some limits and can’t replace actual devices in the real world. The computer you’re using and the pretend devices can affect how well they work together.

• Security Problems

If you’re using the systems of real network devices in a virtual topology, look at the license rules and how you can use them. Also, remember that companies might not offer help or support for their devices used in setups from a security perspective.

Terms of the Network Simulator Program

Graphical Network Simulator Device Features

1. You don’t have to pay a monthly or yearly fee for this emulator program.
2. You can use as many devices as you want in this program, but it depends on your computer’s power, like the brain (CPU) and memory.
3. It supports multiple switching options (ESW16 Etherswitch, IOU/IOL Layer 2, VIRL IOSvL2).
4. It supports all VIRL IOS images (IOSv, IOSvL2, IOS-XRv, CSR1000v, NX-OSv, ASAv).
5. It works with devices from many brands and doesn’t need special software (hypervisor).
6. It works with free and paid hypervisors like Virtualbox, VMware Workstation, VMware Player, ESXi, and Fusion.
7. You don’t need extra virtualization software; a big community of people like and use it.
8. You can get the IOS images from Cisco.com or buy a VIRL license.
9. You must manually add the IOS images you download, such as those for routers or switches.

Which Systems Support GNS3?

• Windows Operating Systems

GNS3 supports all versions of Microsoft Windows, including 7, 8, 8.1, 10, and 11 operating platforms. This allows users to install the network simulator program on these host systems. Additionally, any version of Windows is quite successful in terms of user interface. You can also get more information about installing GNS3 on any version of Windows.

• Linux Distributions

If you like using open-source operating systems, Linux is a good choice. You can run this software on well-known distributions like Ubuntu, Kali, Mint, or Fedora. For example, you can install GNS3 on Ubuntu, which they constantly update.

• macOS Systems

If you have a Mac, you can easily use the network simulation software on your PC, even if it’s running macOS. The installation is straightforward, no matter which version of macOS you have. For detailed instructions, see Running GNS3 on Mac.

What is a GNS3 VM?

GNS3 VM (Graphical Network Simulator 3 Virtual Machine) is part of the simulation software. It works like a virtual machine and aims to enhance both the performance and capabilities of GNS3.

Built on Linux, it functions like a virtual machine technology. This makes it more flexible for creating virtual networks. Also, you can add all kinds of Cisco IOS images from other companies into this VM, giving you more control over your network devices.

You can set the GNS3 Virtual Machine with software such as VMware Workstation, VirtualBox, or Fusion. However, your host PC will require more resources for this setup.

Why Do They Use GNS3 VM?

Many folks like GNS3 VM because it works well and stays stable in complicated network setups. For instance, while the existing software suits simpler designs, it uses VM technology for more advanced ones.

Besides being fast, it also works with different PC systems. So, users can add many systems to what they’re designing.

This software is super important if you’re an experienced network engineer. It excels in tasks like these, enabling you to set things up uniquely. This way, you can design and test more complex structures.

Installing this system on a mighty host allows you to save all your device settings in one place. So, not only do you get more flexibility, but you can also keep better track of your work.

What are the Advantages of Using GNS3 VM?

The network simulator VM agent works pretty simply. For instance, when you open the graphical software, the VM starts simultaneously. Thus, this creates the network connection and data sharing between the two parts.

When it comes to how easy it is to use, here are the benefits:

• Performance

The VM setup lets you make more complicated networks because it works better.

• Guest OS Support

You can use either Windows or other supported systems in your projects.

• Integration

You can easily add the VM setup to different virtualization apps. This helps you make a more detailed network design.

• Custom Configurations

It gives you more power by letting you set up things the way you want, especially for the advanced network designs.

What are the Differences Between GNS3 and Packet Tracer?

If you want to make networks that look and act like real ones, understand how protocols work or fix problems, GNS3 is just what you need. So, if you’re working on a severe topology, using this software that gives advanced support is an intelligent choice.

On the flip side, Packet Tracer software is for people just starting to learn about networks. But here’s the catch—it only works with Cisco stuff. So, you can’t use devices from other companies. In summary, this software is suitable for teaching the basics of networks, especially in a classroom setting.

Comparison Chart

Frequently Asked Questions (FAQ) About GNS3

Conclusion

You can use GNS3 to prepare for Cisco exams instead of purchasing network devices like routers. Plus, you can enhance your networking skills to the fullest extent.

Also, in this network tool, you can use commands that Packet Tracer doesn’t handle for specific routers.