Cisco 2950G 24 - Catalyst Switch Software Configuration Manual page 530

Configuring QoS
Beginning in privileged EXEC mode, follow these steps to configure the port to trust the classification
of the traffic that it receives:
Command
Step 1 configure terminal
Step 2
interface interface-id
Step 3
mls qos trust [cos | dscp]
Step 4
end
Step 5
show mls qos interface [interface-id]
[policers]
Step 6 copy running-config startup-config
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
Interface" section on page
"Configuring the CoS-to-DSCP Map" section on page
Catalyst 2950 Desktop Switch Software Configuration Guide
26-12
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the interface to be
trusted.
Valid interfaces include physical interfaces.
Configure the port trust state.
By default, the port is not trusted.
The keywords have these meanings:
cos—Classifies ingress packets with the packet CoS values. For
tagged IP packets, the DSCP value of the packet is modified based
on the CoS-to-DSCP map. The egress queue assigned to the packet
is based on the packet CoS value.
dscp—Classifies ingress packets with packet DSCP values. For
non-IP packets, the packet CoS value is set to 0 for tagged packets;
the default port CoS is used for untagged packets. Internally, the
switch modifies the CoS value by using the DSCP-to-CoS map. This
keyword is available only if your switch is running the EI.
In software releases earlier than Release 12.1(11)EA1, the
Note
mls qos trust command is available only when the switch is
running the EI.
Use the cos keyword if your network is composed of Ethernet LANs.
Use the dscp keyword if your network is not composed of only
Ethernet LANs and if you are familiar with sophisticated QoS
features and implementations.
For more information about this command, refer to the command
reference for this release.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
26-13. For information on how to configure the CoS-to-DSCP map, see the
Chapter 26
"Configuring the CoS Value for an
26-25.
Configuring QoS
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