: For modern lab testing (equivalent to newer software versions like IOS XE 16 or 17), GNS3 users typically use Cisco's images, which are available through a Cisco Modeling Labs (CML) Cisco Community Cisco 2811 Router IOS Upgrade 25 Apr 2019 —
I started by searching for the Cisco 2811 IOS image online. After a few minutes of searching, I found a reliable source that offered the image for download. However, I was asked to create an account and agree to the terms of use before I could download the image.
In GNS3, the 2811 supports advanced QoS, VPN, MPLS, IPv6, and even some Layer 2 switching via HWIC cards—essential for modern labs.