Differences between Emulation and Simulation

This tutorial explains the key differences between emulation and simulation. Learn what emulation and simulation are and how they work.

Network simulator software uses two methods to create virtual devices. These methods are emulation and simulation. Before we discuss these methods in detail, let's briefly discuss what network simulator software is and why it is used.

Network simulator software

Network simulator software allows you to create network topologies in a virtual environment. In network topologies, you can add many types of networking devices. You can configure and use these devices in the virtual environment the same way you configure and use them in the real environment.

A virtual environment allows you to test and troubleshoot your configuration without messing up the real network. For example, you want to modify a router's configuration on your network, but you are not sure how this change will affect your network. In this situation, you can create your network in the virtual environment and test the change you want to make.

You can also use a virtual environment to practice exam topics. Many networking certification courses need hands-on experience on networking devices. For example, CCNA/CCNP/CCIE exams need hands-on experience on Cisco routers and switches.

Cisco routers and switches are expensive. Purchasing them only for practice is not possible for many students. They can use network simulator software to practice their exam topics. Network simulator software provides a cost-effective solution for hardware devices.

Cisco Packet Tracer, Cisco VIRL, and GNS3 are examples of some popular network simulator software.

Emulation V/s Simulation

If network simulator software creates a virtual copy of a physical device, it is called emulation. If the software uses an emulation process to create a virtual device, the virtual device needs all hardware and software configurations of the physical device. For example, if the physical device needs 256MB of RAM, the virtual copy of the physical device also needs the same amount of RAM. If the physical device needs an IOS to run, the emulated virtual copy of the device also needs the same IOS to run.

If network simulator software creates a virtual copy of the features and functions of the physical device, it is called simulation. If software uses a simulation process to create a virtual device, the virtual device does not need hardware and software configurations of the physical device. It creates a copy of some features, commands, and functions of the physical device and implements them on a virtual device. Since the virtual device provides only some selected functions of the physical device, it needs very less hardware configurations. For example, if a physical device needs 256MB of RAM, the simulated virtual copy of the device may need only 56MB of RAM.

In simple words, in the emulation process, network simulator software makes a copy of the hardware of the actual device. If you emulate a Cisco device, you need the same IOS image file to operate the emulated device that the actual device has.

In the simulation process, the software creates a copy of some selected features and functions of the actual device. If you simulate a device, you don't need any IOS image file or an operating-system file to operate it. The network simulator software automatically installs the minimal OS in each simulated device.

Simulation and emulation on Cisco Packet Tracer, Cisco VIRL, and GNS3

Cisco Packet Tracer does not support emulation. GNS3 supports emulation but does not provide Cisco IOS image files. You have to supply all necessary IOS image files. You can obtain an IOS image file from many sources. You can download it from the Internet, purchase it from Cisco, copy it from a running Cisco device, etc. Cisco VIRL supports emulation. It also includes Cisco IOS images. You can use Cisco VIRL out of the box.

Cisco Packet Tracer, Cisco VIRL, and GNS3 support simulation. They include many in-built simulated devices that you can use to test the running configurations on emulated devices. PCs, Hubs, and layer-2 switches are some examples of simulated devices.

Differences between emulation and simulation

The following table lists key differences between emulation and simulation.

Video version

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That’s all for this tutorial. In this tutorial, we discussed what emulation and simulation are and what the differences between them are.