PS-III Rock Band - Internet Load While Gaming

Question

This inquiry is in regard to bandwidth load created by playing the PS-III version of Rock Band over the Internet. Our internet provider is http://radiowire.net/. Radiowire has set a bandwidth use limit switch at '400 connections per minute'. Not sure what that means... but here lately, the switch has triggered repeatedly. This effectively kills access to the Internet for our home. I am trying to find the cause of this load... considering all possibilities. I am wondering if the kids could be creating this load while playing Rock Band. Their PS-III is connected to our home LAN via WiFi. The WiFi is built into the PS-III and we use a Linksys WiFi unit in our home. FYI... security settings only allow designated MAC addresses to access the network. Any thoughts on this out there?