You can use "show int" or "show int summ" to see the current bandwidth utilization on the router. If you see packets being queued up, that may indicate there is congestion on the router.

Using MRTG to Monitor and Graph Traffic Loads

For further information about MRTG click this link.

http://www.cisco.com/en/US/docs/ios/internetwrk_solutions_guides/splob/guides/dial/dial_nms/mrtg.html

Filtering the traffic sent from controller to the location appliance allows for better bandwidth utilization of links, especially when information has to be sent over WAN links. Processing power on the location appliance is conserved by restricting the information sent from the controller.