Cisco Systems 3560X Manual De Usuario

39-41

Catalyst 3750-X and 3560-X Switch Software Configuration Guide

OL-21521-01

Chapter 39 Configuring QoS

Configuring Standard QoS

Beginning in privileged EXEC mode, follow these steps to configure the port to trust the classification
of the traffic that it receives:

To return a port to its untrusted state, use the no mls qos trust interface configuration command.

For information on how to change the default CoS value, see the

“Configuring the CoS Value for an

Interface” section on page 39-41

. For information on how to configure the CoS-to-DSCP map, see the

“Configuring the CoS-to-DSCP Map” section on page 39-70

Configuring the CoS Value for an Interface

QoS assigns the CoS value specified with the mls qos cos interface configuration command to untagged
frames received on trusted and untrusted ports.

Beginning in privileged EXEC mode, follow these steps to define the default CoS value of a port or to
assign the default CoS to all incoming packets on the port:

Command

Purpose

Step 1

configure terminal

Enter global configuration mode.

Step 2

interface interface-id

Specify the port to be trusted, and enter interface configuration
mode. Valid interfaces are physical ports.

Step 3

mls qos trust

[cos | dscp | ip-precedence]

Configure the port trust state.

By default, the port is not trusted. If no keyword is specified, the
default is dscp.

The keywords have these meanings:

•

cos

—Classifies an ingress packet by using the packet CoS value.

For an untagged packet, the port default CoS value is used. The
default port CoS value is 0.

•

dscp

—Classifies an ingress packet by using the packet DSCP

value. For a non-IP packet, the packet CoS value is used if the
packet is tagged; for an untagged packet, the default port CoS is
used. Internally, the switch maps the CoS value to a DSCP value
by using the CoS-to-DSCP map.

•

ip-precedence

—Classifies an ingress packet by using the packet

IP-precedence value. For a non-IP packet, the packet CoS value
is used if the packet is tagged; for an untagged packet, the default
port CoS is used. Internally, the switch maps the CoS value to a
DSCP value by using the CoS-to-DSCP map.

Step 4

end

Return to privileged EXEC mode.

Step 5

show mls qos interface

Verify your entries.

Step 6

copy running-config startup-config

(Optional) Save your entries in the configuration file.