Patton electronic COPPERLINK 2160 - Manual (Page 55)

Advanced Configuration Options 55
Model 2160 Series User Manual 4 • Web configuration
VLAN Tag Priority Table. Select a packet with an assigned priority to correspond with each queue.
Figure 33. QoS - VLAN Tag Priority Table
Configuration Example. As an example, you can set the Model 2160 to use Weighted Round-Robin (WRR)
queuing that specifies a relative weight of each queue. WRR uses a predefined relative weight for each queue
that determines the percentage of service time to provide each queue before moving on to the next queue. This
prevents the head-of-line blocking that can occur with strict priority queuing.
For this example, set up the WRR (Type 1) to share bandwidth by using scheduling weights 1, 2, 4 and 8 for
queues 0 through 3 respectively.
According to the two tables above, the QoS values map to the Egress Queues as follows:
This example displays that:
• Packets with priority 0 and priority 1 go to Queue 0.
• Packets with priority 2 and priority 3 go to Queue 2.
• Packets with priority 4 and priority 5 go to Queue 3.
• Packets with priority 6 and priority 7 go to Queue 1.
• When, data flow traffic is jammed:
- Queue 1 Packets will go first because weight is equal to 15 (the biggest value).
- Queue 3 Packets will go next because the weight is the second largest value.
- Queue 2 Packets are the next after Queue 3 Packets.
- Queue 0 Packets are the last one to send.
Table 10. WRR Scheduling Configuration Example Values
Queue 0 1 2 3
Type 1
WRR WRR WRR WRR
Weight
1 2 4 8
Priority 0 1 2 3 4 5 6 7
Queue 1 0 0 1 2 2 3 3
Queue
0 1 2 3
Weight
2 15 7 8
Priority 0 1 2 3 4 5 6 7
Queue 0 0 2 2 3 3 1 1