Network diagram app that shows realtime link utilizatin

Hi folks, I wonder if anyone can recommend a network diagram tool that can show realtime link utilization via snmp? Mikrotik's "The Dude" app actually does exactly what I'm looking for, but the snmp support for non-RouterOS devices seems to be lacking, as it simply won't enumerate my switch interfaces in order to capture utilization. I've downloaded several trial tools (WhatsUp, NetCure, Solarwinds LANsurveyor etc.) but they don't serve this very basic need of mine to see the realtime link util in the diagram. Thanks, Hank Disuko