Specifications

114 ExtremeWare XOS 11.0 Concepts Guide

Quality of Service

However, the switch is capable of inserting and/or overwriting 802.1p priority information when it

transmits an 802.1Q tagged frame. If 802.1p replacement is enabled, the 802.1p priority information that

is transmitted is determined by the hardware queue that is used when transmitting the packet. The

802.1p replacement configuration is based on the ingress port. To replace 802.1p priority information,

use the following command:

enable dot1p replacement ports [<port_list> | all]

NOTE

The port in this command is the ingress port.

The 802.1p priority information is replaced according to the hardware queue that is used when

transmitting from the switch. The mapping is described in Table 20. This mapping cannot be changed.

NOTE

This command affects only that traffic based on explicit packet class of service information and

physical/logical configuration.

Configuring DiffServ

Contained in the header of every IP packet is a field for IP Type of Service (TOS), now also called the

Differentiated Services (DiffServ) field. The DiffServ field is used by the switch to determine the type of

service provided to the packet.

Figure 9 shows the encapsulation of an IP packet header.

Table 20: Queue to 802.1p priority replacement value

Hardware Queue 802.1p Priority

Replacement Value