Description: This attribute is a vector which indicates the size and three discard thresholds for receive cell memory for this FP. Receive cell memory is used for storing ATM cells received by this FP which are queued either for handling by the processor on this FP or queued for transmitting over the backplane to other FPs on this switch.

The first value indicates the receive cell memory size. This is derived based on the total receive memory capacity of this FP, and the value of the connectionPoolCapacity and the rxCellMemoryAllocation attributes.

The current value of rxCellMemoryUsage together with the vector of values in rxCellMemoryThresholds determines the rxCellMemoryCongestionState. The congestion state determines whether cells of a given discard priority (DP) are discarded or queued.

When the rxCellMemoryUsage attribute is between threshold 0 and threshold 1, the rxCellMemoryCongestionState indicates the value 0. In congestion state 0, traffic with DP > 0 is discarded. Threshold 1 is set approximately at 90 percent of threshold 0, the total receive cell memory size.

When the rxCellMemoryUsage attribute is between threshold 1 and threshold 2, the rxCellMemoryCongestionState indicates the value 1. In congestion state 1, traffic with DP > 1 is discarded. Threshold 2 is set approximately at 85 percent of threshold 0, the total receive cell memory size.

When the rxCellMemoryUsage attribute is between threshold 2 and threshold 3, the rxCellMemoryCongestionState indicates the value 2. In congestion state 2, traffic with DP > 2 is discarded. Threshold 3 is set approximately at 75 percent of threshold 0, the total receive cell memory size.

When the rxCellMemoryUsage attribute is below threshold 3, the rxCellMemoryCongestionState indicates the value 3. In congestion state 3, traffic with DP=3 is queued.