Table of Contents
Advertisement
20
STEP 1
STEP 2
351
Enter the parameters.
•
Interface—Select the port or LAG.
•
Default CoS—Select the default CoS (Class-of-Service) value to be assigned for
incoming packets (that do not have a VLAN tag).
Click Apply. The interface default CoS value is saved to Running Configuration file.
Queue
The 350 and 550 devices supports 8 queues for each interface. Queue number eight is the
highest priority queue. Queue number one is the lowest priority queue.
There are two ways of determining how traffic in queues is handled, Strict Priority and
Weighted Round Robin (WRR).
•
Strict Priority—Egress traffic from the highest-priority queue is transmitted first.
Traffic from the lower queues is processed only after the highest queue has been
transmitted, thus providing the highest level of priority of traffic to the highest
numbered queue.
•
Weighted Round Robin (WRR)—In WRR mode the number of packets sent from the
queue is proportional to the weight of the queue (the higher the weight the more frames
are sent). For example, if there are a maximum of four queues possible and all four
queues are WRR and the default weights are used, queue 1 receives 1/15 of the
bandwidth (assuming all queues are saturated and there is congestion), queue 2
receives 2/15, queue 3 receives 4/15 and queue 4 receives 8 /15 of the bandwidth. The
type of WRR algorithm used in the device is not the standard Deficit WRR (DWRR),
but rather Shaped Deficit WRR (SDWRR).
The queuing modes can be selected in the Queue page. When the queuing mode is by strict
priority, the priority sets the order in which queues are serviced, starting withthe highest
priority queue and going to the next lower queue when each queue is completed.
When the queuing mode is Weighted Round Robin, queues are serviced until their quota has
been used up and then another queue is serviced.
It is also possible to assign some of the lower queues to WRR, while keeping some of the
higher queues in strict priority. In this case traffic for the strict priority queues is always sent
before traffic from the WRR queues. Only after the strict priority queues have been emptied is
traffic from the WRR queues forwarded. (The relative portion from each WRR queue depends
on its weight).
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
Quality of Service
General
Hide quick links:
Advertisement
Table of Contents
