I86bi-linux-l3-adventerprisek9-ms.155-2.t.bin

Traditional IOS images (like c7200-adventerprisek9-mz.152-4.S.bin ) emulate the entire router hardware—CPU, memory bus, PCI devices, and interfaces—using QEMU or Dynamips. This is slow.

As Cisco moves toward IOS XE in CML 2.0, the pure IOL images are slowly fading. But for the home labber running a 2018 laptop, this 15.5(2)T binary remains the most bang for your virtual buck. i86bi-linux-l3-adventerprisek9-ms.155-2.t.bin

The IOL image, by contrast, uses . It tricks the Cisco routing process into thinking it is running on a specialized Cisco bus, but it actually calls the host Linux kernel directly for process scheduling and memory management. Traditional IOS images (like c7200-adventerprisek9-mz