These emulate older hardware (like Cisco 3725 or 3640) using the Dynamips emulator. While dated, they are great for basic Layer 2/Layer 3 switching fundamentals (VLANs, VTP, STP).
Cisco Virtual Internet Routing Lab (VIRL), now rebranded as , provides official virtual machines for Cisco platforms. The switching image is known as vIOS-L2 (Virtual IOS Layer 2). cisco switch ios image download for gns3 install
You cannot legally download Cisco IOS images from third-party torrent sites, public Google Drives, or file-sharing blogs. These emulate older hardware (like Cisco 3725 or
Dynamips heavily struggles with switching. Legacy router images with switching modules (like the NM-16ESW card on a Cisco 3725) do not support modern switching features like Private VLANs, EtherChannel guard, or advanced Spanning Tree protocols. IOU / IOL (IOS on Unix / IOS on Linux) The switching image is known as vIOS-L2 (Virtual
IOU (IOS on Unix) was originally an internal Cisco tool that runs a version of Cisco’s network operating system as a Linux process. It has since evolved into IOL (IOS on Linux), but the community still commonly refers to them as IOU images. These images are highly efficient, making them perfect for building large topologies on limited hardware.
in the IOS Router Templates window.
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