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Catalyst 3560 Switch Software Configuration Guide
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Chapter 34 Configuring QoS
Configuring Auto-QoS
Tabl e 34-3 shows the generated auto-QoS configuration for the ingress queues.
Tabl e 34-4 shows the generated auto-QoS configuration for the egress queues.
When you enable the auto-QoS feature on the first port, these automatic actions occur:
• QoS is globally enabled (mls qos global configuration command), and other global configuration
commands are added.
• When you enter the auto qos voip cisco-phone interface configuration command on a port at the
edge of the network that is connected to a Cisco IP Phone, the switch enables the trusted boundary
feature. The switch uses the Cisco Discovery Protocol (CDP) to detect the presence or absence of a
Cisco IP Phone. When a Cisco IP Phone is detected, the ingress classification on the port is set to
trust the QoS label received in the packet. The switch also uses policing to determine whether a
packet is in or out of profile and to specify the action on the packet. If the packet does not have a
DSCP value of 24, 26, or 46 or is out of profile, the switch changes the DSCP value to 0. When a
Cisco IP Phone is absent, the ingress classification is set to not trust the QoS label in the packet. The
switch configures ingress and egress queues on the port according to the settings in Table 34-3 and
Tabl e 34-4. The policing is applied to those traffic matching the policy-map classification before the
switch enables the trust boundary feature.
• When you enter the auto qos voip cisco-softphone interface configuration command on a port at
the edge of the network that is connected to a device running the Cisco SoftPhone, the switch uses
policing to determine whether a packet is in or out of profile and to specify the action on the packet.
If the packet does not have a DSCP value of 24, 26, or 46 or is out of profile, the switch changes the
DSCP value to 0. The switch configures ingress and egress queues on the port according to the
settings in Tabl e 34-3 and Tabl e 34-4.
• When you enter the auto qos voip trust interface configuration command on a port connected to
the interior of the network, the switch trusts the CoS value for nonrouted ports or the DSCP value
for routed ports in ingress packets (the assumption is that traffic has already been classified by other
edge devices). The switch configures the ingress and egress queues on the port according to the
settings in Tabl e 34-3 and Tabl e 34-4.
For information about the trusted boundary feature, see the “Configuring a Trusted Boundary to
Ensure Port Security” section on page 34-38.
Tab l e 34-3 Auto-QoS Configuration for the Ingress Queues
Ingress Queue Queue Number CoS-to-Queue Map
Queue Weight
(Bandwidth)
Queue (Buffer)
Size
SRR shared 10, 1 81 percent 67 percent
Priority 22, 3, 4, 5, 6, 7 19 percent 33 percent
Tab l e 34-4 Auto-QoS Configuration for the Egress Queues
Egress Queue Queue Number CoS-to-Queue Map
Queue Weight
(Bandwidth)
Queue (Buffer) Size
for Gigabit-Capable
Ports
Queue (Buffer)
Size for 10/100
Ethernet Ports
Priority 1 5 up to100 percent 16 percent 10 percent
SRR shared 23, 6, 7 10 percent 6 percent 10 percent
SRR shared 32, 4 60 percent 17 percent 26 percent
SRR shared 40, 1 20 percent 61 percent 54 percent