It is not PRTG, MRTG or Cacti. It does not generate webpages as a main feature. I used it a few years back in conjunction with my WRT54G w/ DD-WRT firmware installed. It was a windows application that polled my WRT54G frequently and displayed realtime graphs of what each device connected to it was doing bandwidth-wise. It is fairly simple in comparison to most other applications of this nature, and is free! Help me find it, maybe you used it? I'd like to re-unite with it.

It is also possible that it polled rflow or macupd on my router instead of using SNMP, but I do not think this is the case.