Westermo MR Series - Manual (Page 221)

221 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
Confi gure > Quality of Service > Q Profi les > Q Profi le n 4.72
You may define up to 12 distinct “queue profiles” that may then be assigned to the QOS queues as
required. The queue profile determines how QOS queues with that profile assigned to them will
behave.
Using the Web Page(s)
Each of the Queue Profile pages lists the following parameters:
Minimum Kbps:
This parameter is used to set the minimum data transfer rate in kilobits/sec that the unit will
try to attain for this queue.
Maximum Kbps:
This parameter is used to set the maximum data transfer rate in kilobits/sec that the unit will
try to attain for this queue. This means that if the unit determines that bandwidth is available to
send more packets from a queue that has reached its Minimum Kbps setting, it will send more
packets from that queue until the Maximum Kbps setting is reached.
Note that if you do not want this queue to provide more bandwidth than specified by the
Minimum Kbps setting, this setting should be set to a value the same as or lower than the
Minimum Kbps setting.
Maximum packet Q length:
This parameter specifies the maximum length of a queue (in terms of the number of packets
in the queue). Any packets received that would cause the maximum length to be exceeded are
dropped.
WRED minimum threshold:
This parameter specifies the minimum queue length threshold for using the WRED algorithm to
drop packets. Once the queue length exceeds this value the WRED algorithm may cause packets
to be dropped.
WRED maximum threshold:
This parameter 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
pack ets to be dropped.
WRED maximum drop probability (%)
This parameter is used to set the maximum % probability used by the WRED algorithm to
deter mine 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 0% chance
that a packet will be dropped. When the queue length is between the WRED minimum and
maximum values, the % chance of a packet being dropped increases linearly up to the WRED
maximum drop probability %.
WRED Q length weight factor
This parameter specifies a weighting factor to be used in the WRED algorithm when calculating
the weighted queue length. The weighted queue length is based upon 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 – ½wfact)) + (cur_length × ½wfact)