The signal-bearing medium of claim 2 wherein the steps are repeated until a range of acceptable values for the at least one service level attribute is selected for a range of values of the at least one service variable, whereby each acceptable service level attribute, value is associated with a service variable value, whereby a service level agreement specifying such a range of acceptable values for the at least one service level attribute accommodates a service delivery context in which the valiε of the at least one servicevariable may vary over a range of possible values.