Configuring Queuing And Scheduling - Cisco Nexus 7000 Series Configuration Manual

Configuring Queuing and Scheduling

• The Cisco M3 series module supports only the network-qos template. This template contains all the CoS
• All data traffic will be enqueued to the default queue of dot1q-tunnel port because this port is untrusted
Configuring Queuing and Scheduling
Queuing and scheduling are configured by creating policy maps of type queuing that you apply to either traffic
direction of an interface. You can modify system-defined class maps, which are used in policy maps to define
the classes of traffic to which you want to apply policies.
Additional considerations are as follows:
• Changes to system class maps take effect immediately across all VDCs.
• Changes are disruptive.
• Performance can be impacted.
• If you change the CoS-to-queue mapping by modifying the queuing class maps, you must ensure that a
• If you change the DSCP-to-ingress-queue mapping by modifying the queuing class maps, you must
• By default, nonused queues do not have an allocated buffer. Allocate buffers to these queues to avoid
• Changes to system class-maps are made only on the default VDC.
For information about configuring policy maps and class maps, see "Using Modular QoS CLI."
You can configure the congestion-avoidance features, which include tail drop and WRED, in any queue. You
can configure one of the egress congestion management features, such as priority, shaping, and bandwidth,
in output queues, and you can configure bandwidth in input queues.
We recommend that you modify the CoS value before you create a policy map. You can modify the CoS
values that are matched by device-defined class map queues. You must assign each CoS value from 0 to 7 to
one or more of the queues for each queue type. Each CoS value is used only once in each queue type.
We recommend that you modify the DSCP value before you create a policy map. You can modify the DSCP
values that are matched by device-defined class map queues. You must assign each DSCP value from 0 to 63
to one or more of the queues for each queue type. Each DSCP value is used only once in each queue type.
Cisco Nexus 7000 Series NX-OS Quality of Service Configuration Guide
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values that match the MTU size.
by default.
The specified CoS values immediately map to the new queues.
The traffic passing through ports of the specified port type experience a brief period of traffic loss. All
ports of the specified type are affected. For example, if you change COS-to-queue mapping for the M1
10G egress interface type, all M1 10G ports in all VDCs experience a brief disruption.
If one or more ports of the specified type do not have a queuing policy applied that defines the behavior
for the new queue, then the traffic mapping to that queue might experience performance degradation.
new queuing policy was applied to all ports of that type that use the new queues.
ensure that a new queuing policy is applied to all ports of that type that use the new queues.
tail drop.
Configuring Queuing and Scheduling on M-Series I/O Modules