Cisco Catalyst 4500 Series, Software Configuration Manual

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44-20
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 44 Configuring Quality of Service
Configuring VSS QoS
–
If changing the Precedence or DSCP value is undesirable.
Two Methods for Marking Traffic Attributes
Note This section describes Unconditional marking, which differs from Policer - based marking.
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 .
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 44-4.
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
class class1
set cos 3
end
For information on configuring a policy map, see the “Creating a Policy Map” section on page 44-51.
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 44-51.
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:
table-map table-map1
map from 0 to 1
map from 2 to 3
exit
Table 44-2 set Commands and Applicable Packet Types
set Commands Traffic Attribute Packet Type
set cos Layer 2 CoS value of the outgoing traffic Ethernet IPv4, IPv6
set dscp DSCP value in the ToS byte IPv4, IPv6
set precedence precedence value in the packet header IPv4, IPv6