Reference Guide

Quality of Service (QoS) | 677
• Apply an output policy map to an interface
3. Apply the policy map to an interface. Refer to page 61.
Apply an output QoS policy to a queue
Apply an output QoS policy to queues using the service-queue command from INTERFACE mode.
Specify an aggregate QoS policy
Specify an aggregate QoS policy using the policy-aggregate command from POLICY-MAP-OUT mode.
Apply an output policy map to an interface
Apply an input policy map to an interface using the command service-policy output from INTERFACE
mode. You can apply the same policy map to multiple interfaces, and you can modify a policy map after
you apply it.
QoS Rate Adjustment
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)
By default, while rate limiting, policing, and shaping, FTOS does not include the Preamble, SFD, or the
IFG fields. These fields are overhead; only the fields from MAC Destination Address to the cyclic
redundancy check (CRC) are used for forwarding and are included in these rate metering calculations. You
can optionally include overhead fields in rate metering calculations by enabling QoS Rate Adjustment.
QoS Rate Adjustment is disabled by default.
Task Command Syntax Command Mode
Include a specified number of bytes of packet overhead
to include in rate limiting, policing, and shaping
calculations. For example, to include the Preamble and
SFD, enter qos-rate-adjust 8. For variable length
overhead fields you must know the number of bytes you
want to include.
qos-rate-adjust overhead-bytes
Default: Disabled
S-Series Range: 1-31
CONFIGURATION