- New and Changed Content for QoS CLI Config Guide
- QoS CLI Index
- Preface
- Overview
- Using Modular QoS CLI
- Configuring Classification
- Configuring Marking
- Configuring Mutation Mapping
- Configuring Policing
- Configuring Queuing and Scheduling
- Monitoring QoS Statistics
- Limits Appendix
- Additional References Appendix
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
•Verifying the Mutation Mapping 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 cannot configure system-defined mutation maps. You can only configure those maps that modify the same source and destination variable.
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:
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.
•You can use only like parameters (for example, cos- cos) when you create a mutation map. Mutation maps with dissimilar types (for example, cos-dscp) are not supported.
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.
Note You can set only similar values when you create a mutation map. For example, you can set cos-cos or dscp-dscp; you cannot set cos-dscp or dscp-precedence.
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.
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] {qos-policy-map-name | qos-dynamic}
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 | qos-dynamic} [no-stats]
6. show policy-map [type {qos | queuing}] [policy-map-name | qos-dynamic]
7. copy running-config startup-config
DETAILED STEPS
Verifying the Mutation Mapping Configuration
To display the mutation mapping configuration information, perform one of the following tasks:
|
|
---|---|
show policy-map [type {qos | queuing}] [policy-map-name | qos-dynamic] |
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 4.2.
Example Configuration
The following example shows a mutation configuration:
Note If the child service policy (in this example, child_qos_policy) is not configured in the parent policy map (in this example, parent_policy_for_mutation), all packets will be changed according to the mutation map.
class-map type qos match-all dscp0-12
match dscp 0-12
match protocol dhcp
class-map type qos match-all dscp13-60
match dscp 13-60
table-map mutate_dscp
default copy
from 0 to 0
from 1 to 1
from 2 to 1
from 63 to 46
policy-map type qos child_policy
class dscp0-12
police cir 10 mbps bc 200 ms pir 20 mbps be 200 ms conform transmit exceed set dscp
dscp table mutate_dscp violate drop
class dscp13-63
police cir 20 mbps bc 200 ms pir 40 mbps be 200 ms conform transmit exceed set dscp
dscp table mutate_dscp violate drop
class class-default
police cir 5 mbps bc 200 ms conform transmit violate drop
policy-map type qos parent_policy_for_mutation
class class-default
set dscp dscp table mutate_dscp
service-policy type qos child_qos_policy
Feature History for Mutation
Table 5-1 lists the release history for this feature.
|
|
|
---|---|---|
You can only use similar variables for mutation mapping. |
4.1(2) |
- |
No change |
4.2(1) |
- |