Specifications

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Catalyst 4500 Se ries S wit ch C is co IO S C om mand R efer ence —Re lease I OS XE 3 .3.0 XO(1 5.1 (1)XO)

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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches

qos trust

To set the trusted state of an interface (for example, whether the packets arriving at an interface are

trusted to carry the correct CoS, ToS, and DSCP classifications), use the qos trust command. To set an

interface to the untrusted state, use the no form of this command.

qos trust {cos | device cisco-p hone | dscp | extend [cos priority]}

no qos trust {cos | device cisco-phone | dscp | extend [cos priority]}

Syntax Description

Defaults The default settings are as follows:

• If global QoS is enabled, trust is disabled on the port.

• If global QoS is disabled, trust DSCP is enabled o n the port.

• The CoS priority level is 0.

Command Modes Interface configur ation mode

Usage Guidelines This command is not supported on th e Supervisor Engine 6-E an d Catalyst 4900M chassi s.

You can only configure the trusted state on physi cal LAN interfaces.

By default, the trust state of an interface when QoS is enabled is untrusted; when QoS is disabled on the

interface, the trust state is reset to trust DSCP.

When the interface trust state is qos trust cos, the transmit CoS is always the incoming packet CoS (or

the default CoS for the interface, if the packet is not tagged).

When the interface trust state is not qos trust dscp, the security and QoS ACL classification will always

use the interface DSCP and not the incoming packet DSCP.

Trusted boundary should not be configure d on the ports that are part of an EtherCh annel (that is, a port

channel) .

Examples This example shows how to set the trusted state of an interface to CoS:

Switch(config-if)# qos trust cos

Switch(config-if)#

cos Specifies that the CoS bits in incoming frames are trusted and derives the

internal DSCP value from the CoS bits.

device cisco-phone Specifies the Cisco IP phone as the trust device for a port.

dscp Specifies that the ToS bits in the incoming packets contain a DSCP value.

extend Specifies to extend the trust to Port VLAN ID (PVID) packets coming from

the PC.

cos priority (Optional) Specifies that the CoS priority value is set to PVID packets; valid

values are from 0 to 7.