Queueing And Scheduling On Egress Queues - Cisco WS-C3560-48PS-S Software Configuration Manual

Chapter 28 Configuring QoS

Queueing and Scheduling on Egress Queues

Figure 28-8
If the expedite queue is enabled, SRR services it until it is empty before servicing the other three queues.
Note
Figure 28-8 Queueing and Scheduling Flowchart for Egress Ports
(DSCP or CoS value).
Determine egress queue
number and threshold
Queue the packet. Service
the queue according to
Rewrite DSCP and/or
Each port supports four egress queues, one of which (queue 1) can be the egress expedite queue. These
queues are assigned to a queue-set. All traffic exiting the switch flows through one of these four queues
and is subjected to a threshold based on the QoS label assigned to the packet.
78-16156-01
shows the queueing and scheduling flowchart for egress ports.
Start
Receive packet from
the internal ring.
Read QoS label
based on the label.
Yes
Are thresholds
being exceeded?
No
the SRR weights.
CoS value as
appropriate.
Send the packet
out the port.
Done
Drop packet.
Catalyst 3560 Switch Software Configuration Guide
Understanding QoS
28-15