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This chapter describes the Cisco NX-OS quality of service (QoS) commands that begin with H.
To configure the proxy-queue drain rate settings, use the hardware pq-drain command in global confiiguration mode. To disable proxy-queue drain settings, use the no form of this command.
hardware pq-drain 10g 10g-drain-rate 40g 40g-drain-rate
no hardware pq-drain 10g 10g-drain-rate 40g 40g-drain-rate
Proxy Queue drain rate for the 10 G interface. The range is from 1 Mbps to 20000 Mbps. |
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Proxy Queue drain rate for the 40 G interface. The range is from 1 Mbps to 80000 Mbps. |
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Note This command is applicable to only Cisco Nexus 6000 switches.
When the proxy queue reaches a threshold that indicates congestion, Explicit Congestion Notification (ECN) marking is performed so that the receiver of the packet echoes the congestion indication to the sender. The proxy-queue drain rate is configured to ensure that during congestion at egress ports only a certain amount of packets are drained.
This example shows how to configure proxy-queue settings to drain 9900 Mbps of traffic from 10 Gigabait interfaces and 39900 Mpbs of traffic from 40 Gigabit interfaces:
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To specify the histogram base-value time to construct switch latency monitoring histograms, use the hardware profile latency monitor base command in global configuration mode. To remove switch latency monitoring base values, use the no form of this command.
hardware profile latency monitor base base-value
no hardware profile latency monitor base
Histogram base value used to construct switch latency monitoring histograms. Valid values are multiples of 8 in the range 8 to 2147483640 nanoseconds. |
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Note This command is applicable to Cisco Nexus 6000 switches only.
If you enter a base value that is not a multiple of 8, the system automatically modifies the base value to the nearest (lower) number that is a multiple of 8.
Note All previous histogram statistics are lost when you configure, update or delete the base value.
This example shows how to configure a histogram base value of 800 nanoseconds:
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Specifies the histogram base value to construct switch latency monitoring histograms. |
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Displays switch latency statistics for egress and ingress port pairs. |
To configure the QoS TCAM limit, use the hardware profile tcam feature interface-qos limit command.
hardware profile tcam feature interface-qos limit tcam-size
Interface QoS TCAM limit. The TCAM size can be from 7- 446 entries. |
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No interface policy entry should be present after the interface_qos limit in the QoS region of any TCAM.
This example shows how to set the interface QoS TCAM limit to 20 entries:
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To enable QoS policy offloading on a Fabric Extender (FEX), use the hardware qos-policy-offload command in fabric extender configuration mode. To disable QoS policy offloading, use the no form of this command.
hardware card-type qos-policy-offload
no hardware card-type qos-policy-offload
Fabric extender configuration mode (config-fex)#
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If the existing system-level QoS policy is accepted by the FEX, the QoS policy is enforced by the FEX.
If the existing system-level QoS policy is not accepted by the FEX, an error message is displayed and the fabric ports associated with the FEX are error-disabled, which prevents the FEX from being online.
When you disable the feature, the existing system-level QoS policy is removed from the FEX and the enforcement of the existing QoS policy is changed from ACL-based to Class-of-Service (CoS) based. The TCAM entries are removed and packet classification on the FEX is done using the cos2q map in the FEX hardware.
The maximum number of access control entries (ACEs) in a policy applied on the FEX is 30 when offloaded. In Cisco NX-OS Release 7.3(x), the FEX offload capability using interface QoS policies is up to 100 ACEs and up to only 30 ACEs using system QoS policies.
This example shows how to enable QoS policy offloading on a Cisco Nexus 2248T Fabric Extender:
This example shows how to disable QoS policy offloading on a Cisco Nexus 2248T Fabric Extender:
To configure Explicit Congestion Notification (ECN) for a Quality of Service (QoS) group, use the hardware random-detect command in global configuration mode. To disable ECN, use the no form of this command.
hardware random-detect min-thresh 10g 10g-min-theshold 40g 40g-min-threshold max-thresh 10g 10g-max-threshold 40g 40g-max-threshold ecn qos-group group-number
no hardware randon-detect 10g 10g-min-theshold 40g 40g-min-threshold max-thresh 10g 10g-max-threshold 40g 40g-max-threshold ecn qos-group group-number
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Note This command is applicable to only Cisco Nexus 6000 switches.
To implement Weighted Random Early Detection (WRED) Explicit Congestion Notification (ECN) on proxy queues you use the hardware random-detect command to configure minimum and maximum threshold values per QoS group. Then you use the hardware pq-drain command to configure the proxy-queue drain rate.
This example shows how to enable ECN threshold values for the class-default QoS group:
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To enable the virtual output queuing (VOQ) limit for unicast traffic on a switch, use the hardware unicast voq-limit command. To disable the VOQ limit, use the no form of this command.
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To alleviate congestion and blocking, you can use virtual output queuing (VOQ) to prevent one blocked receiver from affecting traffic that is being sent to other noncongested receivers (head-of-line blocking).
This example shows how to enable the VOQ limits for unicast packets on a switch:
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To limit the number of control packets that can be buffered on the supervisor and destined toward an egress port and a class, use the hardware unicast voq-limit-sup command in the global configuration mode. Use the no form of this command to disable it.
hardware unicast voq-limit-sup
no hardware unicast voq-limit-sup
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In a virtual port channel (vPC) topology, enable the command on both the vPC peers.
Note We recommend that you enable this command under the supervision of Cisco Systems Technical Assistance Center.
This example shows how to limit the number of control packets that can be buffered on the supervisor:
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