Table Of Contents
Configuring Mutation Mapping
Information About Mutation Mapping
Mutation Mapping in Sequence of Traffic Actions
Licensing Requirements for Mutation Mapping
Prerequisites for Mutation Mapping
Guidelines and Limitations
Configuring Mutation Mapping
Verifying the Mutation Mapping Configuration
Example Configuration
Configuring Mutation Mapping
This chapter describes how to configure the mutation of packet values used to define traffic classes.
This chapter includes the following sections:
•
Information About Mutation Mapping
•Licensing Requirements for Mutation Mapping
•Prerequisites for Mutation Mapping
•Guidelines and Limitations
•Configuring Mutation Mapping
•Verifying the Mutation Mapping Configuration
•Example Configuration
Information About Mutation Mapping
Mutation mapping is a method of modifying a QoS field in all packets on an interface. On ingress, mutation mapping occurs before traffic classification and all other actions. On egress, mutation mapping occurs after traffic classification and before the other actions. You can apply mutation mapping to packet fields CoS, DSCP, or IP precedence, or to the internal field discard class.
You use a hierarchical policy map to configure mutation mapping. In the mutation mapping policy map you specify the field to mutate and the policy map to apply with the mutation.
Note The device supports hierarchical policies only for mutation mapping.
Mutation Mapping in Sequence of Traffic Actions
The sequence of QoS actions on ingress traffic is as follows:
1. Queuing and scheduling
2. Mutation
3. Classification
4. Marking
5. Policing
The sequencing of QoS actions on egress traffic is as follows:
1. Classification
2. Marking
3. Policing
4. Mutation
5. Queuing and scheduling
Note Mutation happens much closer to the beginning of the traffic actions on the ingress packets, and any further classification and policing is based on the changed QoS values. Mutation happens at the end of the traffic actions on the egress packets, right before queuing and scheduling.
Licensing Requirements for Mutation Mapping
The following table shows the licensing requirements for this feature:
Product
|
License Requirement
|
NX-OS
|
QoS requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the NX-OS licensing scheme, see the Cisco Nexus 7000 Series NX-OS Licensing Guide, Release 4.0.
|
However, using VDCs requires an Advanced Services license.
Prerequisites for Mutation Mapping
Mutation mapping has the following prerequisites:
•You must be familiar with Chapter 2, "Using Modular QoS CLI."
•You are logged on to the switch.
•You are in the correct virtual device context (VDC). A VDC is a logical representation of a set of system resources. You can use the switchto vdc command with a VDC number.
Guidelines and Limitations
Use the following guidelines to configure mutation mapping:
•You use a hierarchical policy for mutation mapping. Hierarchical policies are not supported for any other use.
•The device supports only one level of hierarchy.
•You can configure up to 14 table maps for use in ingress interfaces and up to 15 table maps for use in egress interfaces.
•Before you delete a referenced policy map, you must first remove all references to that policy map.
Configuring Mutation Mapping
To configure mutation mapping, you create a hierarchical policy map that uses the class-default traffic class to capture all packets and apply mutation mapping to them. You use the service-policy command to specify the policy map to apply with mutation mapping.
To configure mutation mapping, follow these steps:
Step 1 Create the policy map to apply in the mutation mapping hierarchical policy. For information about configuring policy maps, see Chapter 6, "Configuring Policing" or Chapter 7, "Configuring Queuing and Scheduling."
Step 2 Create the table map to use in the mutation mapping hierarchical policy. For information about configuring table maps, see the "Configuring Marking Using Table Maps" section on page 4-13.
Step 3 Configure the mutation mapping hierarchical policy as described in this section.
Step 4 Apply the service policy to the interface. For information about attaching policies to interfaces, see Chapter 2, "Using Modular QoS CLI."
SUMMARY STEPS
1. config t
2. policy-map [type qos] [match-first] policy-map-name
3. class class-default
4. set {cos | discard-class | dscp | precedence} {cos | discard-class | dscp | precedence} table table-map-name
5. service-policy [type qos] policy-map-name [no-stats]
6. show policy-map [type {qos | queuing}] [policy-map-name]
7. copy running-config startup-config
DETAILED STEPS
| |
Command
|
Purpose
|
Step 1
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config t
Example:
switch# config t
switch(config)#
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Enters configuration mode.
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Step 2
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policy-map [type qos] [match-first]
policy-map-name
Example:
switch(config)# policy-map policy1
switch(config-pmap-qos)#
|
Creates or accesses the specified policy map and then enters policy-map mode. The policy map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters.
|
Step 3
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class class-default
Example:
switch(config-pmap-qos)# class
class-default
switch(config-pmap-c-qos)#
|
Configures class-default to capture all traffic in this policy map.
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Step 4
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set {cos | discard-class | dscp |
precedence} {cos | discard-class | dscp
| precedence} table table-map-name
Example:
switch(config-pmap-c-qos)# set dscp dscp
table dscp_mutation
switch(config-pmap-c-qos)#
|
Sets the first packet field to the value of the second packet field based on the mapping values in the specified table map. For mutation mapping, both fields must have the same value. The specified table map must already exist.
The example shows how to use mutation mapping on the DSCP field based on the mapping values in table map dscp_mutation.
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Step 5
|
service-policy [type qos]
policy-map-name [no-stats]
Example:
switch(config-pmap-c-qos)#
service-policy testpolicy
switch(config-pmap-c-qos)#
|
Defines the policy map to apply with the mutation map. The specified policy map must already exist and cannot contain a service-policy command.
Note Classification within this service policy is based on the mutated value, not on the original value in the packet.
Note The service-policy command can only be used for mutation mapping.
|
Step 6
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show policy-map [type {qos | queuing}]
[policy-map-name]
Example:
switch(config-pmap-c-qos)# show
policy-map policy1
|
(Optional) Displays information about all configured policy maps or the specified policy map.
|
Step 7
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copy running-config startup-config
Example:
switch(config-pmap-c-qos)# copy
running-config startup-config
|
(Optional) Saves the running configuration to the startup configuration.
|
Verifying the Mutation Mapping Configuration
To display the mutation mapping configuration information, perform one of the following tasks:
Command
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Purpose
|
show policy-map [type {qos | queuing}] [policy-map-name]
|
Displays information about all configured policy maps or the specified policy map.
|
For detailed information about the fields in the output from these commands, see the Cisco Nexus 7000 Series NX-OS Quality of Service Command Reference, Release 4.0.
Example Configuration
The following example shows a mutation configuration:
class-map type qos match-all dscp0-12
class-map type qos match-all dscp13-60
policy-map type qos child_policy
police cir 10 mbps bc 200 ms pir 20 mbps be 200 ms conform transmit exceed set dscp
dscp table cir-markdown-map violate drop
markdown-map violate drop
police cir 20 mbps bc 200 ms pir 40 mbps be 200 ms conform transmit exceed set dscp
dscp table cir-markdown-map violate drop
markdown-map violate drop
police cir 5 mbps bc 200 ms conform transmit violate drop
policy-map type qos parent_policy_for_mutation
set dscp dscp table mutate_dscp
service-policy type qos child_qos_policy
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