DELL PC2708 User Manual

Packets arriving untagged are assigned a default VPT value, which is set on a per port basis. The 

assigned VPT is used to map the packet to the egress queue.
DSCP values can be mapped to priority queues. DSCP mapping is enabled on a per-system basis. 

The following table contains the default DSCP mapping to egress queue values: 

After packets are assigned to a specific egress queue, CoS services can be assigned to the queue(s). 

Egress queues are configured with a scheduling scheme by one of the following methods:

•

Strict Priority — Strict Priority (SP) allows the prioritization of mission-critical and time-

sensitive traffic over less time-sensitive applications. Thus, ensuring that time-sensitive 

applications are always forwarded before traffic with lower priority. For example, under Strict 

Priority, voice over IP traffic is forwarded before FTP or e-mail (SMTP) traffic. 

•

Weighted Round Robin — Ensures that a single application does not dominate the Ethernet 

switch forwarding capacity. Weighted Round Robin (WRR) forwards entire queues in a 

Round Robin order. All queues can participate in WRR. 

0-15

q1 (Lowest Priority)

16-31

q2

32-47

q3

48-63

q4 (Highest Priority)