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Superior Network Simulators & Emulators for Cisco Certification Exams (CCNA, CCNP, and CCIE)

It is very important to choose an appropriate network emulator or simulator when preparing for your CCNA, CCNP, or CCIE. Of course, this can be a difficult decision to make, especially because there is no best way to make a selection. Unfortunately, it is practically impossible to test each of the programs before making a choice. However, there are specific advantages and disadvantages associated with each of them that can help you make informed decisions.

For the purpose of this blog post, we will focus on two simulators and three emulators. These are GNS3, EVE-NG, VIRL, Boson NetSim, and Packet Tracer. It is essential to mention that they are the most popular programs among the software options designed for developing hands-on experience for the Routing & Switching certification track. Let’s explore these preparation tools based on their categories.


As the name indicates, a simulator refers to the programming software that simulates a network topology made up of one or more network devices. Essentially, the simulated network devices are not actual network ones and do not have the capability of going through live network traffic as a real network device would. Therefore, the simulated ones are restricted to the features and commands that have been programmed into the simulation. This is why a lot of advanced features that the real network devices can optimize are not available in the simulated options. Some of these features include Policy Based Routing and DMVPN.

  • Packet Tracer

This is a visual simulation tool from Cisco. It simulates network topologies that consist of Cisco firewalls, routers, switches, and others. Packet Tracer was first designed as part of the educational aid for NetAcad (Cisco Networking Academy). However, it has become a well-recognized simulator for the entry-level Cisco credentials, including CCENT. It features some advantages as a free network simulator. Top among them are cost, device variety, cross-platform compatibility, connection variety, custom exercise creation, realistic terminal, making lab realistic, and simulation mode. Conversely, the downsides of using the Packet Tracer network simulator include bugs, custom exercise distribution, and no built-in labs. Undoubtedly, all software comes with bugs. However, in Packet Tracer they are more prominent when compared to other programs.

In spite of shortcomings, Packet Tracer is the gold standard as far as virtual network simulators are concerned. The fact that it is free and provides a feature-rich environment for the professionals who want to experiment with large number of network device options, connections, and platforms, makes it a top choice. Due to the limitation in the implementation of simulated Cisco IOS software, Packet Tracer is ideal for the CCENT and the CCNA Routing & Switching certificates, but not for CCIE.

  • Boson NetSim

Boson is a popular IT training organization known for its top-quality coursework and comprehensive practice tests for the Cisco certification exams. The NetSim application is a product of Boson that is designed to simulate Cisco network routers & switches. It is important to mention that this app is a paid network simulator and it also has a couple of benefits. These include lab quality, licensing maps to exams, device customization, lab accessibility, realistic terminal features, custom lab distribution, and less clicking when compared to Packet Tracer.

Boson NetSim definitely has some downsides as well. These include no simulation mode, absence of topology information and customization, inability to modify active topology, and unavailability of cross-platform compatibility.


A network emulator refers to a piece of programming software that optimizes and connects different virtual network devices. It virtualizes the actual network devices, where the virtual ones often provide additional advanced features compared to the simulated network devices. The attributes displayed by the virtual network devices significantly replicate the features of the actual physical ones in the real world.

  • GNS3

GNS3 (Graphic Network Simulator-3) is an open-source, free client/server interface designed for network virtualization and emulation. This software is a Python-based platform using Dynamips primarily to emulate Cisco hardware and software. It is important to mention that Dynamips as well as GNS3, supports Cisco 7200, 3745, 3725, 3600, 2600, and 1700 router platforms. As a free and open-source emulator, GNS3 has a number of benefits. These include cost, easy-to-read and simple documentation, modifiable active topology, community labs, and multiple connection options. The major disadvantage of this emulator is that it doesn’t come with the virtual network devices.

  • VIRL

Virtual Internet Routing Lab (VIRL) is owned by Cisco. It is designed for the individuals and the education institutions. This emulator is similar to CML (Cisco Modeling Labs), a highly scalable option of VIRL created for large and medium businesses to emulate and model enterprise networks. You can install the VIRL server as a virtual machine under ESXi or on the bare metal server. It is important to mention that this emulator functions in the client/server model like GNS3. It is a paid tool that has a couple of benefits. These include network topology portability, advanced automation capabilities, and software image access. The disadvantages include cost, no serial interface, huge resource requirements, and inability to modify active topology.

  • EVE-NG

Emulated Virtual Environment Next Generation (EVE-NG) is comparable to VIRL Personal Edition. It was created for small businesses and those individuals who are looking for a compact emulator. It also has a Professional Edition that costs $110.75 per annum, in addition to a free Community Edition. Some of the core advantages of EVE-NG include multi-connection types, modifiable active topology, cost, and clientless. As a free virtual network emulator, it has two major disadvantages. These are difficulty in documentation and absence of software image access.

Differences between simulators and emulators

Compared to the simulators, the emulators are often restricted in the kinds of virtual network devices they support. They are also limited in terms of how the virtual devices connect to each other. The fact that the network emulators virtualize the actual network devices means that their system prerequisites require more processing power, storage space, and memory, in comparison to the simulators.


There is no one-size-fits-all approach when it comes to simulators and emulators. You have to choose the one that best suits your educational or business needs. We hope that this article will help you make the right decision.