D-Link dgs-1024d/f2a [13/33] Understanding qos

bandwidth be created, but other less critical traffic can be limited, so

bandwidth can be saved. The Switch has separate hardware queues on

every physical port to which packets from various applications are

mapped to and assigned a priority. The illustration below shows how

802.1P priority queuing is implemented on the Switch. The eight IEEE

802.1P priority levels defined by the standard are mapped to the four

class queues used in the Switch.

Mapping QoS on the Switch

The picture above shows the default priority setting for the Switch.

Class-3 has the highest priority of the four priority queues on the Switch.

In order to implement QoS, the user is required to instruct the Switch to

examine the header of a packet to see if it has the proper identifying tag

tagged. Then the user may forward these tagged packets to designated

queues on the Switch where they will be emptied, based on priority.

"The DUT support strict mode for 802.1p QoS. The untagged pkt will

follow the priority 0 to work (i.e. class 1)."

Understanding QoS

The Switch has four priority queues. These priority queues are labeled

as 3, the high queue to 0, the lowest queue. The eight priority tags,

specified in IEEE 802.1p are mapped to the Switch's priority tags as

follows:

 Priority 0 is assigned to the Switch's Q1 queue.

 Priority 1 is assigned to the Switch's Q0 queue.

 Priority 2 is assigned to the Switch's Q0 queue.

 Priority 3 is assigned to the Switch's Q1 queue.