Cisco Catalyst 3750 Command Reference Manual page 44

auto qos voip
When you enable the auto-QoS feature on the first port, these automatic actions occur:
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You can enable auto-QoS on static, dynamic-access, and voice VLAN access, and trunk ports.
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. For more information, see the
To disable auto-QoS on a port, use the no auto qos voip interface configuration command. Only the
auto-QoS-generated interface configuration commands for this port are removed. If this is the last port
on which auto-QoS is enabled and you enter the no auto qos voip command, auto-QoS is considered
disabled even though the auto-QoS-generated global configuration commands remain (to avoid
disrupting traffic on other ports affected by the global configuration). You can use the no mls qos global
configuration command to disable the auto-QoS-generated global configuration commands. With QoS
disabled, there is no concept of trusted or untrusted ports because the packets are not modified (the CoS,
DSCP, and IP precedence values in the packet are not changed). Traffic is switched in pass-through mode
(packets are switched without any rewrites and classified as best effort without any policing).
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 the port is a trusted device:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# auto qos voip trust
You can verify your settings by entering the show auto qos interface interface-id privileged EXEC
command.
Related Commands Command
debug auto qos
mls qos cos
mls qos map
| dscp-cos dscp-list to cos}
mls qos queue-set output buffers
mls qos srr-queue input bandwidth
Catalyst 3750 Switch Command Reference
2-18
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. 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
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 Table 2-2 and Table
{cos-dscp dscp1 ... dscp8
Chapter 2
Table 2-2 and Table 2-3.
2-3.
"debug auto qos" section on page
Description
Enables debugging of the auto-QoS feature.
Defines the default CoS value of a port or assigns the default
CoS to all incoming packets on the port.
Defines the CoS-to-DSCP map or the DSCP-to-CoS map.
Allocates buffers to a queue-set.
Assigns shaped round robin (SRR) weights to an ingress
queue.
Catalyst 3750 Switch Cisco IOS Commands
B-2.
78-16181-01