Cisco Catalyst 3750-X User Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
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

Cisco Catalyst 3750-X Specifications

General

Switching Capacity	160 Gbps
Stacking Bandwidth	64 Gbps
Max Stacking Units	9
Layer Support	Layer 2 and Layer 3
Form Factor	Rack-mountable
DRAM	256 MB
Flash Memory	64 MB
Model	Cisco Catalyst 3750-X Series
Ports	24 or 48 10/100/1000 Ethernet ports
Uplink Interfaces	4 SFP or 2 SFP+
Features	StackWise Plus, EnergyWise
Image	IP Base or IP Services
Operating Temperature	0 to 40°C
Operating Humidity	10 to 85% noncondensing