I need to find a solution to monitor, in real-time, the traffic currently used by an office of about 25 peoples. We already have Zenoss for SNMP monitoring, but I'm looking more at something that would tell me who is using most of the bandwidth "right now". Something similar to this interface: ClearOS Network Traffic Report
Since ClearOS has this functionality, it must not be very hard to reproduce, yet I can't seems to find it in things like PFsense or in Cisco Small business routers.
Any suggestions?