swich utilization

[salsona7]

dear all

first of all i want to know what is swiching capacity and how i know the current utilization of 4950 swich and the maximum allowable capacity? 

another thing how to knonw if the traffic reached the maximum capcity used by this swich  or how to know is swich is out rate or not .

what is the main parameters , characters ,statistics must i know to determine that 4950 is out of rate or cannt able to swich the traffic an how to know these parameters????

thanks for all

mahmoud younis