Cisco Nexus 5000 Series Switch CLI Software Configuration Guide (OL-16597-01, July 2009)

PurposeCommand or Action
(Optional)
Removes the match from the traffic class.
switch(config-cmap-qos)# no match
access-group name acl-name
Step 4
This example shows how to classify traffic by matching packets based on existing ACLs:
switch# configure terminal
switch(config)# class-map type qos class_acl
switch(config-cmap-qos)# match access-group name acl-01
Use the show class-map command to display the ACL class-map configuration:
switch# show class-map class_acl
Configuring CoS Classification
You can classify traffic based on the class of service (CoS) in the IEEE 802.1Q header. This 3-bit field is
defined in IEEE 802.1p to support QoS traffic classes. CoS is encoded in the high order 3 bits of the VLAN
ID Tag field and is referred to as user_priority.
If a system class is configured with a no-drop function, the match cos command serves an additional purpose.
The switch sends the CoS value to the adapter so that the adapter will apply a PFC pause for this CoS value.
The FCoE system class has a default CoS value of 3. You can add a match cos configuration to the FCoE
system class to set a different CoS value. A PFC pause will be applied to traffic that matches the new value.
Procedure
PurposeCommand or Action
Enters configuration mode.switch# configure terminal
Step 1
Creates a named object that represents a class of traffic.
Class-map names can contain alphabetic, hyphen, or
switch(config)# class-map type
qos class-name
Step 2
underscore characters, are case sensitive, and can be up to
40 characters.
Specifies the CoS value to match for classifying packets into
this class. You can configure a CoS value in the range of 0
to 7.
switch(config-cmap-qos)# match
cos cos-value
Step 3
When a Cisco Nexus 2148T Fabric Extender is
connected and in use, data traffic should never be
marked with a CoS value of 7. CoS 7 is reserved for
control traffic transiting the Fabric Extender.
Note
(Optional)
Removes the match from the traffic class.
switch(config-cmap-qos)# no
match cos cos-value
Step 4
This example shows how to classify traffic by matching packets based on a defined CoS value:
switch# configure terminal
switch(config)# class-map type qos class_cos
switch(config-cmap-qos)# match cos 4, 5-6
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
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Configuring System Classes
Configuring CoS Classification