WRED Slope parameters

High Slope

The High Slope parameter specifies how the high-priority packets, also known as in-profile packets, access the shared portion of the buffer pool. The probability of the buffer pools discarding packets is determined by the RED slope. The RED slope is indicated on the client GUI using a graph.

The Start Avg., Max Avg., and Max Prob. parameters specify the values of the RED slope.

In general, packets that are in-profile fall within the configured CIR and PIR ranges. This means the packets are more likely to gain access to the shared buffer pool, and not be discarded because of a buffer overflow.

Low Slope

The Low Slope parameter specifies how the low-priority packets, also known as out-of-profile packets, access the shared portion of the buffer pool. The probability of the buffer pools discarding packets is determined by the RED slope. The RED slop is indicated on the client GUI using a graph.

The Start Avg., Max Avg., and Max Prob. parameters specify the values of the RED slope.

In general, packets that are out-of-profile fall outside configured CIR and PIR ranges. This means the packets should not be allowed to cause a buffer overflow in the shared buffer pool, and should be more likely to be discarded because of a buffer overflow.

Max Avg.

(maxAverage)

The Max Avg. parameter specifies the maximum average of the RED slope position. The parameter indicates that the packet discard probability has increased to 1, and packets are discarded. The range is 0 to 100%. The default is 75% buffer pool utilization before the packet discard probability is 100% for the low slope and 90% for the high slope. The parameter must be greater than or equal to the Start Avg. parameter.

For example, when out-of-profile packets arrive on an interface configured with a low slope policy that has the parameter set to 75% and the Start Avg. parameter set to 50%, out-of-profile packets may start to be discarded by the buffer when it reaches 50% full, and all packets are dropped when the buffer reaches 75% full. The probability of the packets being discarded before the Max Avg. parameter is reached is determined by the Max Prob. parameter.