Cisco Catalyst 2950 Software Manual page 316

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
13-12
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.
Use the cos keyword setting if your network is composed of Ethernet
LANs, Catalyst 2950 switches, and has no more than two types of
traffic.
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.
Enter the cos keyword if you want ingress packets to be classified
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.
Enter the dscp keyword if you want ingress packets to be classified
with packet DSCP values. For non-IP packets, the packet CoS value
is used 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.
For more information on this command, refer to the
Catalyst 2950 Desktop Switch Command Reference.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
13-13. For information on how to configure the CoS-to-DSCP map, see the
Chapter 13
"Configuring the CoS Value for an
13-21.
Configuring QoS
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