The CIR (Committed Information Rate) specifies the minimum data rate guaranteed to the relevant subscriber. The MIR (Maximum Information Rate) value specifies the maximum data rate available for burst transmissions, provided such bandwidth is available. Under normal conditions, the actual Information Rate (IR) is between the applicable CIR and MIR values, based on the following
formula: IR=CIR+K(MIR - CIR).
In this formula K is between 0 and 1 and is determined dynamically by the AU according to overall demand in the cell and the prevailing conditions that influence the performance of the wireless link. In some situations the minimum rate (CIR) cannot be provided. This may result from high demand and poor wireless link conditions and/or high demand in over-subscribed cells.