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Cisco 12000/10700 v3.1.1 Router Manager User Guide
OL-4455-01
Chapter 11 Layer 3 QoS
CoS Queue Group Configurati on
IP Precedence
The IP Precedence area contains a table with two headings: IP Precedence and Drop Label.
IP Precedence—This column allows the user to map packets that have a particular IP precedence to a
WRED profile in this CoS queue group. You can map several or all preceden ces to the same WRE D
profile if you wish. By default, precedence values are mapped so that they are not dropped due to WRED.
Drop Label—Choose a number, 0 to 6 o r no-drop, which is the number of th e corresponding dr op label
in the WRED parameters table.
All—On checking All, the configuration of the first IP precedence is applied to all the Ip precedences.
WRED Parameters
The WRE D Parame ter s a rea c onta ins a ta ble wit h f ou r h eading s : Dro p L a bel, Mi n Th re shold, M ax
Threshold, and Max Prob Denominator. The last three headings describe the actual WRED curve.
Drop Label—Drop label is a placeholder number for this set of WRED parameters. This is the number
you map IP precedence values to.
Min Threshold—When the weighted queue average is below the minimum threshold, no packets are
dropped.
Max Th r es h old —When the weighted queue average is above the maximum queue threshold, all packets
are dropp ed unt il the average drops bel ow the ma ximum thre shold .
Max Prob Denominator—When the weigh ted queu e av erage is between th e minimu m and the max imum
thresholds, the probability that the packet is going to be dropped can be calculated by a straight line from
the minimum thresho ld (prob ability of drop will be 0 ) to the ma ximum thr eshold (pro babil ity of dro p is
equal to the max pr ob denomi nator).