Difference Between CatOS and Cisco IOS System Software
CatOS on the Supervisor Engine and Cisco IOS Software on the MSFC (Hybrid): a CatOS image can be used as the system software to run the Supervisor Engine on the Catalyst 6500/6000 switches. If the optional MSFC is installed, a separate Cisco IOS® Software image is used in order to run the MSFC. CatOS provides the Layer 2 (L2) switching functionality. The Cisco IOS on the MSFC provides the Layer 3 (L3) routing functionality.
Cisco IOS Software on both the Supervisor Engine and MSFC (Native): a single Cisco IOS Software image can be used as the system software to run both the Supervisor Engine and MSFC on the Catalyst 6500/6000 switches.
