Cisco Catalyst 3550 Command Reference Manual page 48

auto qos voip
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You can enable auto-QoS on static, dynamic-access, voice VLAN access, and trunk ports. When
enabling auto-QoS with a Cisco IP Phone on a routed port, you must assign a static IP address to the IP
phone.
Note When a device running Cisco SoftPhone is connected to a switch or routed port, the switch supports only
one Cisco SoftPhone application per port.
After auto-QoS is enabled, do not modify a policy map or aggregate policer that includes AutoQoS in its
name. If you need to modify the policy map or aggregate policer, make a copy of it, and change the
copied policy map or policer. To use the new policy map instead of the generated one, remove the
generated policy from the interface, and apply the new policy map.
To display the QoS configuration that is automatically generated when auto-QoS is enabled, enable
debugging before you enable auto-QoS. Use the debug auto qos privileged EXEC command to enable
auto-QoS debugging.
To disable auto-QoS on an interface, use the no auto qos voip interface configuration command. When
you enter this command, the switch enables standard QoS and changes the auto-QoS settings to the
standard-QoS default settings for that interface.
To disable auto-QoS on the switch, use the no mls qos global configuration command. When you enter
this command, the switch disables QoS on all interfaces and enables pass-through mode.
Examples This example shows how to enable auto-QoS and to trust the QoS labels received in incoming packets
when the switch or router connected to an interface is a trusted device:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# auto qos voip trust
This example shows how to enable auto-QoS and to trust the QoS labels received in incoming packets
when the device connected to an interface is detected as a Cisco IP Phone:
Switch(config)# interface fastethernet0/1
Switch(config-if)# auto qos voip cisco-phone
Catalyst 3550 Multilayer Switch Command Reference
2-22
QoS is globally enabled (mls qos global configuration command).
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 interface is set
to trust the QoS label received in the packet. When a Cisco IP Phone is absent, the ingress
classification is set to not trust the QoS label in the packet. The egress queues on the interface are
also reconfigured (see Table
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 decide 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 egress queues on the interface are also reconfigured (see
When you enter the auto qos voip trust interface configuration command on a port connected to
the interior of the network, the ingress classification on the interface is set to trust the QoS label
received in the packet, and the egress queues on the interface are reconfigured (see
Chapter 2
2-2).
Catalyst 3550 Switch Cisco IOS Commands
Table 2-2).
Table
OL-8566-02
2-2).