16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series
Configuration Tasks
89
Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ
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 89
. For information on how to configure the CoS-to-DSCP map, see the
“Configuring the CoS-to-DSCP Map” section on page 96
.
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:
Step 3
mls qos trust {cos | dscp}
Configures 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.
Enter the dscp keyword if you are using an SVI that is a VLAN
interface that you created by using the interface vlan vlan-id global
configuration command. The DCSP-to-CoS map will be applied to
packets arriving from a router to the Ethernet switch network module
through an SVI.
Step 4
end
Returns to privileged EXEC mode.
Step 5
show mls qos interface [interface-id]
[policers]
Verifies your entries.
Step 6
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Command
Purpose
Command
Purpose
Step 1
configure terminal
Enters global configuration mode.
Step 2
interface interface-id
Enters interface configuration mode, and specify the interface to be trusted.
Valid interfaces include physical interfaces.