Users Guide

1. Apply the policy-map to the interface in INTERFACE mode or all interfaces in SYSTEM-QOS mode.
system qos
OR
interface ethernet node/slot/port[:subport]
2. Enter the output service-policy in SYSTEM-QOS mode or INTERFACE mode.
service-policy {output} type {queuing} policy-map-name
Enable strict priority on class-map and apply the policy-map globally
OS10(config)# class-map type queuing example-cmap-strictpriority
OS10(config-cmap-queuing)# match queue 7
OS10(config-cmap-queuing)# exit
OS10(config)# policy-map type queuing example-pmap-strictpriority
OS10(config-pmap-queuing)# class example-cmap-strictpriority
OS10(config-pmap-c-que)# priority
OS10(config-pmap-c-que)# exit
OS10(config-pmap-queuing)# exit
OS10(config)# system qos
OS10(config-sys-qos)# service-policy output type queuing example-pmap-strictpriority
Enable strict priority on interface
NOTE: You can apply a policy-map globally in SYSTEM-QOS mode or apply it on the interface. OS10 does not support
applying the same policy-map in SYSTEM-QOS mode as well as at the interface level.
However, you can apply a different queuing policy-map in SYSTEM-QOS mode or at the interface level. In this case, the
policy-map applied at the interface takes precedence over the policy-map applied globally.
OS10(config)# interface ethernet 1/1/5
OS10(conf-if-eth1/1/5)# service-policy output type queuing example-pmap-strictpriority
View policy-map
OS10(conf-if-eth1/1/5)# do show policy-map
Service-policy(queuing) output: example-pmap-strictpriority
Class-map (queuing): example-cmap-strictpriority
priority
Configuration notes
Dell EMC PowerSwitch S4200-ON Series:
If PFC is provisioned, the control packets injected by CPU shares queue-7 while egressing on a front panel interface. If queues
other than queue-7 are provisioned as strict priority, it is recommended to provision queue-7 as strict priority too, to reduce
latency or loss of control packets.
Rate adjustment
QoS features such as policing and shaping do not include overhead fields such as Preamble, smart frame delimiter (SFD),
inter-frame gap (IFG), and so on. For rate calculations, these feature only include the frame length between the destination
MAC address (DMAC) and the CRC field.
You can optionally include the following overhead fields in rate calculations by enabling rate adjustment:
● Preamble—7 bytes
● Start frame delimiter—1 byte
● Destination MAC address—6 bytes
● Source MAC address—6 bytes
● Ethernet type/length—2 bytes
● Payload—variable
● Cyclic redundancy check—4 bytes
1326
Quality of service