DELL S50V User Manual

Quality of Service | 869

Specify an aggregate QoS policy using the command 

 from POLICY-MAP-OUT mode.

Apply an input policy map to an interface using the command 

 

 from INTERFACE 

mode. You can apply the same policy map to multiple interfaces, and you can modify a policy map after 
you apply it.

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 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, and no 

 is listed in the running-configuration.

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 

8. For variable length 

overhead fields you must know the number of bytes you 
want to include.

qos-rate-adjust overhead-bytes

Default: Disabled
C-Series and S-Series Range: 1-31
E-Series Range: 1-144

CONFIGURATION