Here is something which has been troubling my mind lately. The basic question is, how do I turn an in and an out into an aggregate? Here is a scenario: I measure usage on a customer's T1 at my router port. Every 5 minutes a sample the port and figure the average bps both in and out for the last five minutes. Now, I want to make a number that represents the aggregate usage across that port but, I cannot simply add the two ins and outs (as I am doing now) because they were both averages over a period of time. Doing this produces some strange effects which can show nice trends but also lies about the real usage. Perhaps I simply lack the math experience to do this correctly but I can't see a good way to do it. Brian Horvitz WebSecure, Inc.