Cisco ME 3600X, Command Reference Manual

Page: 260 / 628

2-236
Cisco ME 3800X and ME 3600X Switch Command Reference
OL-28238-01
Chapter 2 Cisco ME 3800X and ME 3600X Switch Cisco IOS Commands
random-detect precedence
When you configure the random-detect command on a policy class, packets are given preferential
treatment based on the IP Precedence of the packet. Use the random-detect precedence command to
adjust the treatment for different precedences.
If you want WRED to ignore the precedence when determining which packets to drop, enter this
command with the same parameters for each precedence. Remember to use reasonable values for the
minimum and maximum thresholds.
Table 5 lists the default minimum threshold value for each IP Precedence.
Examples The following example configures policy for a class called acl10 included in a policy map called
policy10. Class acl101 has these characteristics:
a minimum of 2000 kbps of bandwidth are expected to
be delivered to this class in the event of congestion and a weight factor of 10 is used to calculate the
average queue size. For congestion avoidance, WRED packet drop is used, not tail drop. IP Precedence
is reset for levels 0 through 4.
policy-map policy10
class acl10
bandwidth 2000
random-detect
random-detect exponential-weighting-constant 10
random-detect precedence 0 32 256 100
random-detect precedence 1 64 256 100
random-detect precedence 2 96 256 100
random-detect precedence 3 120 256 100
random-detect precedence 4 140 256 100
Related Commands
Table 5 Default WRED and DWRED Minimum Threshold Values
Minimum Threshold Value
(Fraction of Maximum Threshold Value)
IP Precedence WRED DWRED
0 9/18 8/16
1 10/18 9/16
2 11/18 10/16
3 12/18 11/16
4 13/18 12/16
5 14/18 13/16
6 15/18 14/16
7 16/18 15/16
Command Description
bandwidth (policy-map class) Specifies or modifies the bandwidth allocated for a class
belonging to a policy map.
random-detect dscp Changes the minimum and maximum packet thresholds for the
DSCP value.
random-detect
exponential-weighting-constant Configures the WRED and DWRED exponential weight factor for
the average queue size calculation.