Dell S4048-ON, Руководство по настройке

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Example of the
show qos statistics egress-queue
Command
Pre-Calculating Available QoS CAM Space
Before Dell 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 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 (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 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 {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.
Specifically:
• Available CAM — the available number of CAM entries in the specified CAM partition for the specified line card or stack-unit
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
Example of the
test cam-usage
Command
Dell# test cam-usage service-policy input pmap_l2 port-set 0 | port pipe
Port-pipe | CAM Partition | Available CAM | Estimated CAM | Status
=====================================================================
0 L2ACL 500 200 Allowed(2)
Configuring Weights and ECN for WRED
The WRED congestion avoidance functionality drops packets to prevent buffering resources from being consumed. Traffic is a
mixture of various kinds of packets. The rate at which some types of packets arrive might be greater than others. In this case, the
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Quality of Service (QoS)