Resolution
IP routing is enabled by default. However, IP routing does not work if what must be routed is not configured on the switch. This is because the switch has a built-in router.
IP routing cannot be disabled on the Supervisor 720 (Sup 720). However, the ports can all be configured as Layer 2 (L2) ports. The ports can all be L2 access ports in particular VLANs, which can accomplish the desired effect.
The no ip routing is a classical IOS command used to disable IP routing on routers. This command is usually used on low-end routers, on Cat 6k this command doesn't make sense hence, command will not be saved across reload if entered. When you enter the no ip routing command you may get a console message: "Cannot disable ip routing on this platform"
Note: When IP routing is enabled, the cpu resources are wasted in performing the Layer 3 (L3) computation. Hence when L3 functionality is not needed, do not configure it.
