Prerequisites For Queuing And Scheduling; Guidelines And Limitations - Cisco Nexus 7000 Series Configuration Manual

Configuring Queuing and Scheduling on F-Series I/O Modules
port group). Finally, if all the port groups are removed from a given VDC with this feature enabled, the shared
buffering for that VDC with no ports is returned to the default disabled state.
After you enable shared buffering, the shared buffer pools are configured, using the active template, on the
default ingress queuing policy. If you change the template, the setting for shared buffering remains as you
last set this feature, either enabled or disabled. Then, the shared buffers are reconfigured based on the ingress
queuing policy of the new template. If no user-defined policies are attached to a port group, the same default
ingress queuing policy is applied to the shared buffer pool as to the dedicated buffer pool.
Note
You cannot change the template if you have any user-defined policies attached to the port group. You must
first remove all user-defined queuing policies from the port group, and then you can change the template.
If you enable and configure shared buffer queuing, the shared buffer pools are used before the dedicated buffer
queues. Any necessary dropped packets come from the dedicated buffer pools and pause is always honored
from the dedicated buffer pools.
Note
The cos2q maps and the dscp2 maps are global in scope. The same maps are applied to the shared buffer
pools.

Prerequisites for Queuing and Scheduling

Queuing and scheduling have the following prerequisites:
• You must be familiar with "Using Modular QoS CLI."
• You are logged on to the switch.
• You are in the correct VDC. A VDC is a logical representation of a set of system resources. You can use

Guidelines and Limitations

Queuing and scheduling of F-Series modules have the following configuration guidelines and limitations:
• A queuing policy that is being activated should be consistent with the system network qos policy.
• The default queuing policy is attached to the system target (includes all F Series module ports), which
• A queuing policy that is attached to a given port, overrides the system queuing policy on that port.
• The DSCP to egress queue selection for DSCP values 2-7 are set to be the same as the values for CoS
• Egress policies on VLAN configurations do not support set match on CoS.
• Egress policies on VLAN configurations do not support set QoS group or discard class.
the switchto vdc command with a VDC number.
is unlike the M1 series configuration where the default-in-policy is attached exclusively to each port.
2-7. To change this setting, access the type QoS policy and use the set cos command to change the selected
egress queue (applicable for all types of interfaces, such as access, trunk, routed, and so on).
Cisco Nexus 7000 Series NX-OS Quality of Service Configuration Guide
Prerequisites for Queuing and Scheduling
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