lp Eng Arc Aqm Tx Cell Threshold Table

This attribute is a vector which indicates the size and three discard thresholds for transmit cell memory for the ATM Queue Manager (AQM) ASIC on this FP. Transmit cell memory is used for storing ATM cells to be transmitted by connections. It includes all cells in all connections at all service categories. The first value indicates the transmit cell memory size. It is the amount of transmit memory which is available for cell queueing, after the amount of memory specified by connectionPoolCapacity. The current value of txCellMemoryUsage together with the vector of values in txCellMemoryThresholds determines the txCellMemoryCongestionState. The congestion state determines whether cells of a given discard priority (DP) are discarded or queued for transmit. When the txCellMemoryUsage attribute is between threshold 0 and threshold 1, the txCellMemoryCongestionState 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 transmit cell memory size. When the txCellMemoryUsage attribute is between threshold 1 and threshold 2, the txCellMemoryCongestionState 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 transmit cell memory size. When the txCellMemoryUsage attribute is between threshold 2 and threshold 3, the txCellMemoryCongestionState 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 transmit cell memory size. When the txCellMemoryUsage attribute is below threshold 3, the txCellMemoryCongestionState indicates the value 3. In congestion state 3, traffic with DP=3 is queued.