Enabling Qos Rate Adjustment; Enabling Strict-Priority Queueing - Dell S6100 Configuration Manual

Applying an Output Policy Map to an Interface
To apply an output policy map to an interface, use the following command.
• Apply an input policy map to an interface.
INTERFACE mode
service-policy output
You can apply the same policy map to multiple interfaces, and you can modify a policy map after you apply it.

Enabling QoS Rate Adjustment

By default while rate limiting, policing, and shaping, Dell Networking OS does not include the Preamble, SFD, or the IFG fields. These fields
are overhead; only the fields from MAC destination address to the CRC are used for forwarding and are included in these rate metering
calculations.
The Ethernet packet format consists of:
• Preamble: 7 bytes Preamble
• Start frame delimiter (SFD): 1 byte
• Destination MAC address: 6 bytes
• Source MAC address: 6 bytes
• Ethernet Type/Length: 2 bytes
• Payload: (variable)
• Cyclic redundancy check (CRC): 4 bytes
• Inter-frame gap (IFG): (variable)
You can optionally include overhead fields in rate metering calculations by enabling QoS rate adjustment.
QoS rate adjustment is disabled by default.
• Specify the number of bytes of packet overhead to include in rate limiting, policing, and shaping calculations.
CONFIGURATION mode
qos-rate-adjust overhead-bytes
For example, to include the Preamble and SFD, type qos-rate-adjust 8. For variable length overhead fields, know the number of
bytes you want to include.
The default is disabled.

Enabling Strict-Priority Queueing

In strict-priority queuing, the system de-queues all packets from the assigned queue before servicing any other queues. You can assign
strict-priority to one unicast queue, using the strict-priority command.
• Policy-based per-queue rate shaping is not supported on the queue configured for strict-priority queuing. To use queue-based rate-
shaping as well as strict-priority queuing at the same time on a queue, use the Scheduler Strict feature as described in Scheduler
Strict .
• The strict-priority supersedes bandwidth-percentage configuration.
• A queue with strict priority can starve other queues in the same port-pipe.
• Assign strict priority to one unicast queue.
INTERFACE mode
service-policy output policy-map-name
712 Quality of Service (QoS)