Concept Guide

Displaying WRED Drop Statistics
To display WRED drop statistics, use the following command.
• Display the number of packets Dell EMC Networking OS the WRED prole drops.
EXEC Privilege mode
show qos statistics wred-profile
Example of the show qos statistics wred-profile Command
DellEMC#show qos statistics wred-profile
Interface Te 1/1
Drop-statistic Dropped Pkts
Green 51623
Yellow 51300
Out of Profile 0
DellEMC#
Displaying egress–queue Statistics
To display the number of transmitted and dropped packets and their rate on the egress queues of an interface, use the following command:
• Display the number of packets and number of bytes on the egress-queue prole.
EXEC Privilege mode
show qos statistics egress-queue
Example of show qos statistics egress-queue Command
Pre-Calculating Available QoS CAM Space
Before Dell EMC Networking OS version 7.3.1, there was no way to measure the number of CAM entries a policy-map would consume (the
number of CAM entries that a rule uses is not predictable; from 1 to 16 entries might be used per rule depending upon its complexity).
Therefore, it was possible to apply to an interface a policy-map that requires more entries than are available. In this case, the system writes
as many entries as possible, and then generates an CAM-full error message (shown in the following example). The partial policy-map
conguration might cause unintentional system behavior.
%EX2YD:12 %DIFFSERV-2-DSA_QOS_CAM_INSTALL_FAILED: Not enough space in L3
Cam(PolicyQos) for class 2 (TeGi 12/20) entries on portpipe 1
The test cam-usage command allows you 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 congurations. This command measures the size of the specied
policy-map and compares it to the available CAM space in a partition for a specied port-pipe.
Test the policy-map size against the CAM space for a specic port-pipe or all port-pipes using these commands:
• test cam-usage service-policy input policy-map {stack-unit } number port-set number
• test cam-usage service-policy input policy-map {stack-unit } 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.
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Quality of Service (QoS)