Auto Qos Voip - Cisco 4500M Command Reference Manual

auto qos voip

auto qos voip
To automatically configure quality of service (auto-QoS) for voice over IP (VoIP) within a QoS domain,
use the auto qos voip interface configuration command. Use the no form of this command to change the
auto-QoS configuration settings to the standard QoS defaults.
Syntax Description
cisco-phone
trust
Defaults
Auto-QoS is disabled on all interfaces.
Command Modes
Interface configuration
Command History Release
12.1(19)EW
Usage Guidelines
Use this command to configure the QoS appropriate for VoIP traffic within the QoS domain. The QoS
domain includes the switch, the interior of the network, and the edge devices that can classify incoming
traffic for QoS.
Use the cisco-phone keyword on ports at the edge of the network that are connected to Cisco IP phones.
The switch detects the telephone through the Cisco Discovery Protocol (CDP) and trusts the CoS labels
in packets received from the telephone.
Use the trust keyword on ports connected to the interior of the network. Because it is assumed that traffic
has already been classified by other edge devices, the CoS/DSCP labels in these packets are trusted.
When you enable the auto-QoS feature on the specified interface, these actions automatically occur:
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Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW
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auto qos voip {cisco-phone | trust}
no auto qos voip {cisco-phone | trust}
Connects the interface to a Cisco IP phone and automatically configures QoS for
VoIP. The CoS labels of incoming packets are trusted only when the telephone is
detected.
Connects the interface to a trusted switch or router and automatically configures
QoS for VoIP. The CoS and DSCP labels of incoming packets are trusted.
Modification
Support for this command was introduced on the Catalyst 4500 series switch.
QoS is globally enabled (qos global configuration command).
DBL is enabled globally (qos dbl global configuration command).
When you enter the auto qos voip cisco-phone interface configuration command, the trusted
boundary feature is enabled. It 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
specific interface is set to trust the CoS label received in the packet because some old phones do not
mark DSCP. When a Cisco IP phone is absent, the ingress classification is set to not trust the CoS
label in the packet.
Chapter2 Cisco IOS Commands for the Catalyst 4500 Series Switches
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