Chapter 4 | Advanced Configuration |
None
If the None option is selected, then the Router prioritizes each packet based on the required level of service for its four LAN ports, using four priority queues with strict or Weighted Round Robin (WWR) queuing. You can use these functions to assign independent priorities for delay- sensitive data and
When a port is set to None mode, then the Router will not check CoS VLAN tag priority or DSCP/ToS priority bits in the IP header.
CoS
If the CoS option is selected, then the Router will use CoS- based QoS in Layer 2. This type of QoS lets you specify which data packets have higher priority when traffic is buffered due to congestion. Data packets in high priority queues will be transmitted before those in the lower priority queues. You can map eight priority levels to the Router’s input queues. If the port is configured as CoS mode, then the order of importance for the application of priority rules are as follows: 1) CoS, 2) DSCP, and 3) None
DSCP
If the Differentiated Services Code Point (DSCP) option is selected, then the Router will use
Default CoS Select the default CoS priority value, 0 to 7, with 0 being the lowest priority.
CoS Settings
Priority This is the CoS value, 0 to 7 (7 is the highest priority).
Queue Select the traffic forwarding queue number to which the CoS priority is mapped. You can designate up to four traffic priority queues configured on the Queue Settings screen.
To reset the CoS queue settings to their factory defaults, click Restore Defaults. The defaults are 2, 1, 1, 2, 3, 4, and 4 for the Priority values, 0 to 7.
Click Save Settings to save your changes, or click Cancel Changes to undo them.
QoS > Queue Settings
You can set the Router to service the queues based on a strict rule that requires all traffic in a higher priority queue to be processed before lower priority queues are serviced, or you can set the Router to use Weighted Round Robin (WWR) queuing, which specifies a relative weight of each queue. WRR uses a predefined relative weight for each queue, which determines the percentage of service time the Router services each queue before moving on to the next queue. This prevents
QoS > Queue Settings
Queue Settings
Queue The number of the queue, 1 to 4, is displayed (4 is the highest priority queue).
Strict Priority With Strict Priority, the Router services the egress queues in sequential order, so all traffic in the higher priority queues is transmitted before the lower priority queues are serviced. To base traffic scheduling on queue priority, select Strict Priority. The WRR Weight will be 1, 2, 4, and 8, respectively, for queues 1 to 4.
WRR WithWRR, the Router shares bandwidth at the egress ports using scheduling weights 1, 2, 4, and 8, respectively, for queues 1 to 4. If you want to use WRR queuing, select WRR.
WRR Weight If you selected WRR, set a new weight for the selected traffic class, within the range of 1 to 15. (Queue 1 is fixed at a weight of 1, and it cannot be changed.)
%of WRR Bandwidth This is the percentage of bandwidth used by WRR. This automatically changes if you change the WRR Weight for a queue.
Click Save Settings to save your changes, or click Cancel Changes to undo them.
QoS > DSCP Settings
Traffic priorities can be specified in the IP header of a frame. With Differentiated Services Code Point (DSCP)-
29 |