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29-46
Catalyst 2960 Switch Software Configuration Guide
78-16881-01
Chapter 29 Configuring QoS
Configuring Standard QoS
Step 3
policy-map policy-map-name Create a policy map by entering the policy map name, and enter
policy-map configuration mode.
By default, no policy maps are defined.
The default behavior of a policy map is to set the DSCP to 0 if the
packet is an IP packet and to set the CoS to 0 if the packet is tagged.
No policing is performed.
Step 4
class class-map-name Define a traffic classification, and enter policy-map class configuration
mode.
By default, no policy map class-maps are defined.
If a traffic class has already been defined by using the class-map global
configuration command, specify its name for class-map-name in this
command.
Step 5
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,
go to Step 6.
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 29-51.
Step 6
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.
Command Purpose