User`s guide

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WRED Maximum Threshold
The value in this text box specifies the maximum queue length threshold for using the
WRED algorithm to drop packets. Once the queue length exceeds this value, the WRED
algorithm will cause all packets to be dropped.
WRED Maximum Drop Probability (%)
The value in this text box sets the maximum percentage probability used by the WRED
algorithm to determine whether or not a packet should be dropped when the queue length
is approaching the WRED maximum threshold value.
Note:
If the length of a queue is less than the WRED minimum threshold value there is a 0%
chance that a packet will be dropped. When the queue length is between the WRED
minimum and maximum values, the % probability of a packet being dropped increases
linearly up to the WRED maximum drop probability.
WRED Queue Length Weight factor
The value in this text box specifies a weighting factor to be used in the WRED algorithm
when calculating the weighted queue length. The weighted queue length is based on the
previous queue length and has a weighting factor that may be adjusted to provide different
transmit characteristics. The actual formula used is:
new_length = (old_length * (1-1/2^n)) + (current_length * 1/2^n)
Small weighting factor values result in a weighted queue length that moves quickly and
more closely matches the actual queue length. Larger weighting factor values result in a
queue length that adjusts more slowly. If a weighted queue length moves too quickly (small
weighting factor), it may result in dropped packets if the transmit rate rises quickly but will
also recover quickly after the transmit rate tails off. If a weighted queue length moves too
slowly (large weighting factor), it will allow a burst of traffic through without dropping
packets, but may result in dropped packets for some time after the actual transmit rate
drops off. The weighting factor should be selected carefully to suit the type of traffic using
the queue.
Related CLI Commands
Entity
Instance
Parameter
Values
Equivalent Web Parameter
qprof n minkbps 0 - 2147483647 Minimum kbps
qprof n maxkbps 0 - 2147483647 Maximum kbps
qprof n qlen 0 - 2147483647 Maximum Packet Queue Length
qprof n minth 0 - 2147483647 WRED Minimum Threshold
qprof n maxth 0 - 2147483647 WRED Maximum Threshold
qprof n mprob 0 - 100
WRED Maximum Drop
Probability (%)
qprof n wfact 0 - 2147483647
WRED Queue Length Weight
factor
Command line examples.
To display a queue profile, enter the following command:
gqprof <instance> ?
Where <instance> is the number of the queue profile to be displayed.
To change the value of a parameter, use the following command: