3Com 10014299 manual Discard-prob, Ip-precedence

700 CHAPTER 50: CONGESTION AVOIDANCE

Configure the WRED weighted factor for	qos wred weighting-constant exponent
calculating the WRED average queue
length.
Recover the default value of the WRED	undo qos wred weighting-constant
weighted factor for calculating the WRED
average queue length.

exponent is the filtering coefficient for calculating the average queue length, and the range of the value is 1 to 16, and the default value is 9.

When exponent=0 and the queue length exceeds the threshold, WRED will act accordingly. When exponent is higher, WRED will act slowly to the change of queue status.

This configuration should be performed after enabling WRED in the interface view.

Set the Priority You can set WRED drop lower threshold value, upper threshold value, and drip Parameters for WRED probability denominator according to packet priority. The reciprocal value of the

denominator discard-probwill be taken as the maximum drop probability. The system will handle the queues according to the length of the queues.

■If the queue length is lower than the low-limit, no packet will be dropped.

■If the queue length is between low-limitand high-limit, the drop probability will increase with the queue length till it is almost equal to the reciprocal value of discard-prob.

■If the queue length is equal to or greater than high-limit, all the packets will be dropped.

Please perform the following configurations in the interface view.

Table 740 Configure the Related Parameters for the Packets of Specific IP Priority

Operation	Command
Configure the related parameters for the	qos wred ip-precedence ip-precedence
packets of specific IP priority	low-limit low-limithigh-limit
	high-limitdiscard-probability
	discard-prob
Recover the default values of the related	undo qos wred ip-precedence
parameters for the packets of specific IP	ip-precedence
priority

ip-precedenceis the IP precedence, and the range of the value is 0 to 7.

low-limitand high-limitare the minimum and maximum thresholds respectively. The default values are 10 and 30 respectively, and the range of the value is 1 to 1024.

discard-probis the drop probability denominator and its default value is 10. The reciprocal of discard-probwill be the maximum drop probability. The range of this parameter is 1 to 255.

It should be noted that this configuration can only be performed after WRED is enabled in interface view.