Cisco Catalyst 2960 Software Configuration Manual page 755

Chapter 33 Configuring QoS
Priority Queueing
Catalyst 2960-S switches do not support ingress queueing.
Note
You can configure one ingress queue as the priority queue by using the mls qos srr-queue input
priority-queue queue-id bandwidth weight global configuration command. The priority queue should
be used for traffic (such as voice) that requires guaranteed delivery because this queue is guaranteed part
of the bandwidth regardless of the load on the stack or internal ring.
SRR services the priority queue for its configured weight as specified by the bandwidth keyword in the
mls qos srr-queue input priority-queue queue-id bandwidth weight global configuration command.
Then, SRR shares the remaining bandwidth with both ingress queues and services them as specified by
the weights configured with the mls qos srr-queue input bandwidth weight1 weight2 global
configuration command.
You can combine the commands described in this section to prioritize traffic by placing packets with
particular DSCPs or CoSs into certain queues, by allocating a large queue size or by servicing the queue
more frequently, and by adjusting queue thresholds so that packets with lower priorities are dropped. For
configuration information, see the
Queueing and Scheduling on Egress Queues
Figure 33-8
If the expedite queue is enabled, SRR services it until it is empty before servicing the other three queues.
Note
OL-26520-01
"Configuring Ingress Queue Characteristics" section on page
shows the queueing and scheduling flowchart for egress ports.
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
Understanding QoS
33-71.
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