Hi all,  anybody know any routers (wireless or otherwise) which provide the ability to monitor the WAN usage from each LAN ip (by month or better).  Ie for IP 192.168.1.1 I can see how much traffic it generated.  Or alternatively by MAC address would be OK too (maybe better). 

Don't want to fiddle about with it too much, hoping there might be one of the open firmwares available that do it?