Reference Guide

CONFIGURATION mode
Dell(conf)#service-class wred ecn 0, 3-5, 7 backplane
Pre-Calculating Available QoS CAM Space
Pre-calculating available QoS CAM space allows you to measure the number of CAM entries a policy-map consumes.
This feature allows you to avoid applying a policy-map on an interface that requires more CAM entries than are available and
receive a CAM full error message (shown in the following example). The partial policy-map configuration might cause
unintentional system behavior.
%EX2YD:12 %DIFFSERV-2-DSA_QOS_CAM_INSTALL_FAILED: Not enough space in L3
Cam(PolicyQos) for class 2 (Te 12/20) entries on portpipe 1 for linecard 12
%EX2YD:12 %DIFFSERV-2-
DSA_QOS_CAM_INSTALL_FAILED: Not enough space in L3 Cam(PolicyQos) for class 5 (Te
12/
22) entries on portpipe 1 for linecard 12
Use the test cam-usage command to verify that there are enough available CAM entries before applying a policy-map to an
interface so that you avoid exceeding the QoS CAM space and partial configurations. This command measures the size of the
specified policy-map and compares it to the available CAM space in a partition for a specified port-pipe.
Test the policy-map size against the CAM space for a specific port-pipe or all port-pipes using these commands:
● test cam-usage service-policy input policy-map linecard {0–2} number port-set number
● test cam-usage service-policy input policy-map linecard {0–2} all
The output of this command, shown in the following example, displays:
● The estimated number of CAM entries the policy-map will consume.
● Whether or not the policy-map can be applied.
● The number of interfaces in a port-pipe to which the policy-map can be applied.
Specifically:
● Available CAM — the available number of CAM entries in the specified CAM partition for the specified line-card port pipe.
● Estimated CAM — the estimated number of CAM entries that the policy will consume when it is applied to an interface.
● Status — indicates whether the specified policy-map can be completely applied to an interface in the port-pipe.
○ Allowed — indicates that the policy-map can be applied because the estimated number of CAM entries is less or equal
to the available number of CAM entries. The number of interfaces in the port-pipe to which the policy-map can be
applied is given in parentheses.
○ Exception — indicates that the number of CAM entries required to write the policy-map to the CAM is greater than the
number of available CAM entries, and therefore the policy-map cannot be applied to an interface in the specified port-
pipe.
NOTE:
The show cam-usage command provides much of the same information as the test cam-usage command, but
whether a policy-map can be successfully applied to an interface cannot be determined without first measuring how many
CAM entries the policy-map would consume; the test cam-usage command is useful because it provides this
measurement.
● Verify that there are enough available CAM entries.
test cam-usage
Dell# test cam-usage service-policy input pmap_l2 linecard 0 port-set 0
Linecard | Port-pipe | CAM Partition | Available CAM | Estimated CAM | Status
===============================================================================
0 0 L2ACL 500 200 Allowed(2)
Quality of Service (QoS)
625