Cisco Catalyst 4500 Series Configuration Manual page 883

Chapter 40 Configuring Quality of Service
Two Methods for Marking Traffic Attributes
This section describes Unconditional marking, which differs from Policer-based marking.
Note
Unconditional marking is based solely on classification.
Method One: Unconditional Explicit Marking (using the set command)
You specify the traffic attribute you want to change with a set command configured in a policy map. The
following table lists the available set commands and the corresponding attribute. For details on the set
command, refer to the Catalyst 4500 Series Switch Command Reference.
Table 40-2 set Commands and Applicable Packet Types
set Commands Traffic Attribute
set cos Layer 2 CoS value of the outgoing traffic
set dscp DSCP value in the ToS byte
set precedence precedence value in the packet header
set qos-group QoS group ID
If you are using individual set commands, those set commands are specified in a policy map. The
following is a sample of a policy map configured with one of the set commands listed in Table 40-2.
In this sample configuration, the set cos command has been configured in the policy map (policy1) to
mark the CoS attribute:
enable
configure terminal
policy map p1
end
For information on configuring a policy map, see the "Creating a Policy Map" section on page 40-15.
The final task is to attach the policy map to the interface. For information on attaching the policy map
to the interface, see the "Attaching a Policy Map to an Interface" section on page 40-16.
Method Two: Unconditional Tablemap-based Marking
You can create a table map that can be used to mark traffic attributes. A table map is a kind of two-way
conversion chart that lists and maps one traffic attribute to another. A table map supports a many-to-one
type of conversion and mapping scheme. The table map establishes a to-from relationship for the traffic
attributes and defines the change to be made to the attribute. That is, an attribute is set to one value that
is taken from another value. The values are based on the specific attribute being changed. For instance,
the Precedence attribute can be a number from 0 to 7, while the DSCP attribute can be a number from 0
to 63.
The following is a sample table map configuration:
table-map table-map1
map from 0 to 1
OL-25340-01
To leverage a large range of traffic classes. The QoS group value has 64 different individual
–
markings, similar to DSCP.
– If changing the Precedence or DSCP value is undesirable.
class class1
set cos 3
Packet Type
Ethernet IPv4, IPv6
IPv4, IPv6
IPv4, IPv6
Ethernet, IPv4, IPv6
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
Configuring QoS
40-19