Archives For Network Simulation

open-source network simulation tools that run on Linux or BSD systems

EVE-NG and UNetLab are graphical network emulators that support both commercial and open-source router images. UNetLab is the current, stable version of the network emulator and EVE-NG is an updated version of the same tool, available as an alpha release. The UNetLab/EVE-NG network emulator runs in a virtual machine so it can be set up Windows, Mac OS, or Linux computers. Its graphical user interface runs in a web browser.

In this post, I will show how to set up an EVE-NG virtual machine on an Ubuntu Linux system. I’ll show the basic steps to creating and running a simple lab consisting of emulated Linux nodes. The procedure is the same for UNetLab.

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OFNet SDN network emulator

November 20, 2016 — 1 Comment

OFNet is a new software-defined network (SDN) emulator that offers functionality similar to the Mininet network emulator and adds some useful tools for generating traffic and monitoring OpenFlow messages and evaluating SDN controller performance.


OFNet is an open-source project that is distributed as a virtual machine (VM) image. The OFNet source code is available in the OFNet VM’s filesystem. In this post, we will use the OFNet VM provided by the OFNet developer to run SDN emulation scenarios in OFNet.

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Roland Kuebert forked the psimulator2 network simulator project from the original, seemingly discontinued source and made the new version available at

Roland posted this announcement in the comments under my psimulator2 blog post. So that his announcement receives a bit more visibility, I am re-posting his comment verbatim below:

Hi all,

Just a heads up, I forked the project from the original, seemingly discontinued source and it is available at .

I have fixed the issue preventing the use of Java 8, but I have yet to look into making a release on GitHub. You can, however, clone the repository and use gradle to build jar files – I recommend using gradle shadowJar to create jar files which can be run without specifying any further dependencies.

For the frontend, use java -jar java -jar frontend/build/libs/psimulator-frontend-master-*.jar (replace the asterisk with the exact name, the star represents the git commit you used to checkout).

For the backend, use java -jar backend/build/libs/psimulator-backend-master-*-all.jar (replace the asterisk with the exact name, the star represents the git commit you used to checkout).


VirtualBox is an open-source virtual machine manager and hypervisor that may also be used as a network emulator. In addition to creating and managing individual virtual machines, VirtualBox can connect virtual machines together to emulate a network of computers and network appliances such as routers or servers. VirtualBox works on the major computing platforms: Windows, MacOS, and Linux.

In this post, I offer a step-by-step tutorial showing how to use the VirtualBox graphical user interface to set up a network of six devices: three routers and three PCs. This tutorial will utilize some of the advanced functions supported by VirtualBox and provide you with the skills to set up a network of virtual machines on your own personal computer.

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This post lists the commands required on each node to build a network of three Ubuntu Linux routers. Each router is connected to the other two routers and is running quagga. Each router is also connected to a PC running Ubuntu Linux.


I use this network configuration to evaluate network emulators and open-source networking software in a simple scenario. Readers may find these commands useful in building their own configuration scripts.

I provide “copy and paste” commands so the network can be configured quickly.

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dCore Linux is a minimal Linux system based on the Tiny Core Linux system. Like Tiny Core Linux, dCore loads its file system entirely into RAM, which should provide good performance in large network emulation scenarios running on a single host computer.

dCore Linux allows users to install additional software from the Debian or Ubuntu repositories, instead of using the pre-built (and often out-of-date) TCE extensions provided for Tiny Core Linux. This should simplify the process of building network appliances for use in a network emulator, as you will not need to compile and build your own extensions, or use out-of-date pre-built extensions.

dCore Linux is designed to run as a “live” Linux system from removable media such as a CD or a USB drive but, for my use, I need to install it on a hard drive. Currently available instructions for installing dCore Linux onto a hard drive are incomplete and hard to follow. This post lists a detailed procedure to install dCore Linux on a virtual disk image connected to a virtual machine. I use VirtualBox in this example, but any other virtual machine manager would also be suitable.

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Mininet-WiFi is a fork of the Mininet SDN network emulator. The Mininet-WiFi developers extended the functionality of Mininet by adding virtualized WiFi stations and access points based on the standard Linux wireless drivers and the 80211_hwsim wireless simulation driver. They also added classes to support the addition of these wireless devices in a Mininet network scenario and to emulate the attributes of a mobile station such as position and movement relative to the access points.


The Mininet-WiFi extended the base Mininet code by adding or modifying classes and scripts. So, Mininet-WiFi adds new functionality and still supports all the normal SDN emulation capabilities of the standard Mininet network emulator.

In this post, I describe the unique functions available in the Mininet-WiFi network emulator and work through a few tutorials exploring its features.

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To learn more about OpenStack cloud management software, a student or researcher may install OpenStack on a single machine, such as a laptop computer or a virtual machine, and emulate a small datacenter using virtual machines or containers.


Researchers and students may choose from multiple projects that will set up OpenStack on a single machine. Some projects are community-based open-source projects and others are vendor supported projects (while still nominally open-source).

This post is an overview of links and resources to installing OpenStack on one machine.

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OpenDaylight (ODL) is a popular open-source SDN controller framework. To learn more about OpenDaylight, it is helpful to use it to manage an emulated network of virtual switches and virtual hosts. Most people use the Mininet network emulator to create a virtual SDN network for OpenDaylight to control.


In this post, I will show how to set up OpenDaylight to control an emulated Mininet network using OpenFlow 1.3. Because I am using virtual machines, the procedure I use will work the same in all commonly used host systems: Linux, Windows, and Mac OS X.

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The Cloonix network simulator has been updated to version 29, which adds the ability to save network simulation topologies and node configurations to a directory.

Users may save a network topology and all node configurations to a directory of their choice. They may also load saved topologies into Cloonix so they can restore a network scenario they previously created. The save function of Cloonix v29 supports copy-on-write filesystems and also allows users to save the full filesystems of nodes, if they wish.

This post will work through a detailed tutorial showing how to save, load, and re-save topologies and node configurations using the Cloonix GUI or command-line interface.

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The Cloonix development team recently released a major update to the Cloonix network simulator.

Cloonix version 28 makes major changes to the infrastructure of Cloonix. It changes the installation procedure, the location of Cloonix files on your computer, and the names of the commands used to start and administer Cloonix.


Cloonix version 28 also makes changes to the features available to users. It adds support for multiple Cloonix servers running on the same machine, and standardizes and documents the new interface types used to connect virtual machines to each other.

Read the rest of this post for more details about what’s new in Cloonix v28.

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When using open-source network simulators that use KVM as a virtualization tool, each node in the network simulation is actually a KVM virtual machine so the maximum supported number of nodes in a network simulation is the same as the maximum number of KVM virtual machines that can run on the host computer.

Unfortunately, there seems to be no single authoritative statement about the maximum number of KVM virtual machines that can run on a host computer. Most information I could find about KVM limits does not publish absolute limits but, instead, recommends best practices.

In this post, I will synthesize the information available from many different sources into a single recommendation for the maximum number of KVM-based nodes that can run in an open-source network simulator running on a single host computer.

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