Question : Monitor interface bandwidth on Cisco PIX

I'm very new to Cisco stuff so I appologize if this question is dumb.  We have a shared T1 internet connection between my company and another company in the building.  I would like to know who is using most of it.  We have a Cisco PIX firewall that splits the connection, one interface going to our switch and the other interface going to the other company's switch.

Looking in the GUI on the PIX, I see a monitoring tab.  I've build a graph using "byte counts" for both interfaces.  I notice that there is an Input and an Output value for each interface.  What exactly is the difference in these values.  Is this a good graph to judge which company is using the bandwidth?

Answer : Monitor interface bandwidth on Cisco PIX

SNMP is a great way to go and you can get a free snmp server to monitor these things.  The nice thing about doing it this way is you can monitor it as long as the SNMP server is running and it will store the information.  You coulde leave ASDM open all of the time but that can be a pain.  I would use bit rates over byte counts though so you do not have to do any conversion.