looking for a tool...

[Mike <mike-nanog () tiedyenetworks com>]

Hello,

    I was wondering if anyone could point me in the direction of a tool 
capable of sniffing (or reading pcap files), and reporting on lan 
station thruput in terms of bits per second. Ideally I'd like to be able 
to generate a sorted report of the top users and top thruputs observed 
and so forth. The traffic is pppoe and I need to monitor it at a 
specific switchport where I can arrange span.

Thank you.