Cisco Catalyst 3750-E Software Configuration Manual page 871

Chapter 37 Configuring QoS
Figure 37-10
(DSCP or CoS value).
Determine ingress queue
number, buffer allocation,
and WTD thresholds.
being exceeded?
Queue the packet. Service
the queue according to
the SRR weights.
SRR services the priority queue for its configured share before servicing the other queue.
Note
The switch supports two configurable ingress queues, which are serviced by SRR in shared mode only.
Table 37-1
Table 37-1
Queue Type
Normal
Expedite
1. The switch uses two nonconfigurable queues for traffic that is essential for proper network and stack operation.
OL-9775-08
Queueing and Scheduling Flowchart for Ingress Ports on Catalyst 3560-E Switches
Start
Read QoS label
Yes
Are thresholds
No
Send packet to
the internal ring.
describes the queues.
Ingress Queue Types
1
Function
User traffic that is considered to be normal priority. You can configure three different
thresholds to differentiate among the flows. You can use the mls qos srr-queue input
threshold, the mls qos srr-queue input dscp-map, and the mls qos srr-queue input
cos-map global configuration commands.
High-priority user traffic such as differentiated services (DF) expedited forwarding or
voice traffic. You can configure the bandwidth required for this traffic as a percentage
of the total traffic or total stack traffic on Catalyst 3750-E switches by using the mls
qos srr-queue input priority-queue global configuration command. The expedite queue
has guaranteed bandwidth.
Drop packet.
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
Understanding QoS
37-17