Dell Force10 S50-01-GE-48T FTOS 8.4.2.7 Configuration Guide for E-Series TeraS - Page 869

Specify an aggregate QoS policy Specify an aggregate QoS policy using the command policy-aggregate 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 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 qos-rate-adjust is listed in the running-configuration. Task Command Syntax 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 C-Series and S-Series Range: 1-31 E-Series Range: 1-144 Command Mode CONFIGURATION Quality of Service | 869