GNS3 vs ns-3

GNS3 is free, open-source software for emulating, configuring, testing, and troubleshooting virtual and real networks. Its graphical client works with a virtual machine, and servers can run locally or remotely. Users can combine emulated devices running actual images with simulated devices, including a built-in layer 2 switch. It supports appliances from vendors such as Cisco, Brocade, Cumulus Linux, and HPE, as well as Docker, QEMU-based appliances, VMware, VirtualBox, Hyper-V, and connections to real networks. The GNS3 Marketplace offers preconfigured appliance templates with recommended settings. It runs on Windows, macOS, and Linux; documentation recommends the GNS3 VM for most Windows and macOS setups and complex topologies. Users must supply their own Cisco IOS images. There are no monthly or yearly license fees, and device capacity depends in practice on the host computer’s CPU and memory. GNS3 is used for networking education, certification practice, proofs of concept, demonstrations, and interoperability testing. A server has no authentication enabled by default and should be restricted at the network level.

ns-3 is a free, discrete-event network simulator for research and education. It supports simulations of IP and non-IP networks, including wireless work involving Wi-Fi and LTE, and provides a workflow from configuring a simulation through collecting and analyzing traces. A real-time scheduler supports simulation-in-the-loop use, including sending and receiving ns-3 packets on real network devices. Its Direct Code Execution framework can run C or C++ applications or the Linux kernel networking stack within ns-3.

The project is available for Linux, macOS, Windows, and self-hosted use, with desktop deployment listed. It is free software under GNU GPLv2, priced at free. Releases arrive roughly two or three times each year, mainly as compressed source archives. Documentation includes tutorials, installation guidance, model library material, a reference manual, and Doxygen API documentation. NetAnim and Bake are listed as related tools. Support channels include mailing lists, Zulip chat, and the issue tracker; the project says volunteers maintain it without company backing.