Guidelines And Limitations - Cisco Nexus 9000 Series Configuration Manual

Guidelines and Limitations

Guidelines and Limitations

Queuing and scheduling have the following configuration guidelines and limitations:
• show commands with the internal keyword are not supported.
• The device supports a system-level queuing policy, so all ports in the system are impacted when you
• A type queuing policy can be attached to the system or to individual interfaces for input or output traffic.
• Changes are disruptive. The traffic passing through ports of the specified port type experience a brief
• Performance can be impacted. If one or more ports of the specified type do not have a queuing policy
• Traffic shaping might increase the latency of packets due to queuing because it falls back to
• Traffic shaping is not supported on the Cisco Nexus 9300 ALE 40G ports. For more information on
• When configuring priority for one class map queue (SPQ), you need to configure the priority for QoS
• About queue limits for 100G enabled devices (such as the Cisco Nexus 9300 Series switch with the
• 100G enabled devices (such as the Cisco Nexus 9300 Series switch with the N9K-M4PC-CFP2 GEM),
• FEX support for:
• When the switch supported system queuing policy is configured, the FEX uses the default policy.
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
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configure the queuing policy.
period of traffic loss. All ports of the specified type are affected.
applied that defines the behavior for the new queue, the traffic mapping to that queue might experience
performance degradation.
store-and-forward mode when packets are queued.
ALE 40G uplink ports, see the
Switches.
group 3. When configuring priority for more than one class map queue, you need to configure the priority
on the higher numbered QoS groups. In addition, the QoS groups need to be adjacent to each other. For
example, if you want to have two SPQs, you have to configure the priority on QoS group 3 and on QoS
group 2.
N9K-M4PC-CFP2 GEM):
◦ The maximum dynamic queue-limit alpha value supported by the device might be greater that 8.
However 8 is the maximum alpha value supported. Configuring the alpha value to a value greater
than 8 is overridden by the maximum alpha value of 8.
No message is issued when the alpha value is overridden.
◦ The static queue-limit has a maximum of 20,000 cells. Any value specified greater than the
maximum 20,000 cell limit is overridden by the 20,000 cell limit.
No message is issued when the cell limit is overridden.
the WRED threshold has a maximum of 20,000 cells. Any value specified greater than the maximum
20,000 cell limit is overridden by the 20,000 cell limit.
No message is issued when the cell limit is overridden.
◦ System input (ingress) level queuing for HIF to NIF traffic.
◦ System output (egress) level queuing for NIF to HIF traffic and HIF to HIF traffic.
Limitations for ALE 40G Uplink Ports on the Cisco Nexus 9000 Series
Configuring Queuing and Scheduling