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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 39 Configuring QoS
Understanding QoS
Queueing and Scheduling Overview

The switch has queues at specific points to help prevent congestion as shown in Figure 39-6 and

Figure 39-7.

Figure 39-6 Ingress and Egress Queue Location on Catalyst 3750-X Switches
Figure 39-7 Ingress and Egress Queue Location on Catalyst 3560-X Switches

Because the total inbound bandwidth of all ports can exceed the bandwidth of the stack or internal ring,

ingress queues are located after the packet is classified, policed, and marked and before packets are

forwarded into the switch fabric. Because multiple ingress ports can simultaneously send packets to an

egress port and cause congestion, outbound queues are located after the stack or internal ring.

MarkerPolicer
MarkerPolicer
Marker
Ingress
queues
Stack ring Egress
queues
Policer
MarkerPolicer
Classify
Traffic SRRSRR
86691
MarkerPolicer
MarkerPolicer
Marker
Ingress
queues
Internal
ring Egress
queues
Policer
MarkerPolicer
Classify
Traffic SRRSRR
90563