I have a Cisco 2811 and we are trying to solve a bandwidth usage problem. Is there a way to determine what host IP is using all the bandwidth on the Serial port?
Probably the easiest way to determine that is to configure NetFlow on the router. NetFlow will generate statistics that will identify addresses, protocols, and amount of traffic. It would be especially interesting to configure the option in NetFlow to identify the Top Talkers. This link has information about this:
It seems that it would be just what you need.