Cisco Catalyst 4500 series Administration Manual page 1046

Configuring QoS on a Standalone Supervisor Engine 6-E/6L-E or Supervisor Engine 7-E/7L-E/8-E
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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 42-4 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 42-4.
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 42-51.
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 42-51.
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:
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
42-54
particular IP precedence or DSCP and strict priority can then be configured to put all packets of that
marking into that queue. In this case, the marking was used to identify traffic for strict priority
queue.
Traffic marking can be used to identify traffic for any class-based QoS feature (any feature available
in policy map class configuration mode, although some restrictions exist).
class class1
set cos 3
Chapter 42
Packet Type
Ethernet IPv4, IPv6
IPv4, IPv6
IPv4, IPv6
Ethernet, IPv4, IPv6
Configuring Quality of Service
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