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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 39 Configuring QoS Configuring Standard QoS
Step 18 trust [cos | dscp | ip-precedence]Configure the trust state, which QoS uses to generate a CoS-based or
DSCP-based QoS label.
Note This command is mutually exclusive with the set command
within the same policy map. If you enter the trust command,
omit Step 18.
By default, the port is not trusted. If no keyword is specified when the
command is entered, the default is dscp.
The keywords have these meanings:
cos—QoS derives the DSCP value by using the received or default
port CoS value and the CoS-to-DSCP map.
dscp—QoS derives the DSCP value by using the DSCP value from
the ingress packet. For non-IP packets that are tagged, QoS derives
the DSCP value by using the received CoS value; for non-IP
packets that are untagged, QoS derives the DSCP value by using
the default port CoS value. In either case, the DSCP value is
derived from the CoS-to-DSCP map.
ip-precedence—QoS derives the DSCP value by using the IP
precedence value from the ingress packet and the
IP-precedence-to-DSCP map. For non-IP packets that are tagged,
QoS derives the DSCP value by using the received CoS value; for
non-IP packets that are untagged, QoS derives the DSCP value by
using the default port CoS value. In either case, the DSCP value is
derived from the CoS-to-DSCP map.
For more information, see the “Configuring the CoS-to-DSCP Map”
section on page 39-70.
Step 19 set {dscp new-dscp | ip precedence
new-precedence}
Classify IP traffic by setting a new value in the packet.
For dscp new-dscp, enter a new DSCP value to be assigned to the
classified traffic. The range is 0 to 63.
For ip precedence new-precedence, enter a new IP-precedence
value to be assigned to the classified traffic. The range is 0 to 7.
Step 20 service-policy policy-map-name Specify the interface-level policy-map name (from Step 10) and
associate it with the VLAN-level policy map.
If the VLAN-level policy map specifies more than one class, each class
can have a different service-policy policy-map-name command.
Step 21 exit Return to policy-map configuration mode.
Step 22 exit Return to global configuration mode.
Step 23 interface interface-id Specify the SVI to which to attach the hierarchical policy map, and
enter interface configuration mode.
Command Purpose