Applying an Output Policy Map to an InterfaceTo apply an output policy map to an interface, use the following command.• Apply an input policy map to an interface.INTERFACE modeservice-policy outputYou can apply the same policy map to multiple interfaces, and you can modify a policy map after you apply it.Enabling QoS Rate AdjustmentBy default while rate limiting, policing, and shaping, Dell Networking OS does not include the Preamble, SFD, or the IFG fields. These fieldsare overhead; only the fields from MAC destination address to the CRC are used for forwarding and are included in these rate meteringcalculations.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 modeqos-rate-adjust overhead-bytesFor example, to include the Preamble and SFD, type qos-rate-adjust 8. For variable length overhead fields, know the number ofbytes you want to include.The default is disabled.Enabling Strict-Priority QueueingIn strict-priority queuing, the system de-queues all packets from the assigned queue before servicing any other queues. You can assignstrict-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 SchedulerStrict .• 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.CONFIGURATION modestrict-priority682 Quality of Service (QoS)
