EVC Quality of Service

This document contains information about how to enable quality of service (QoS) features (such as traffic classification and traffic policing) for use on an Ethernet virtual circuit (EVC).

An EVC as defined by the Metro Ethernet Forum is a port-level point-to-point or multipoint-to-multipoint circuit. It is an end-to-end representation of a single instance of a service being offered by a provider to a customer. It embodies the different parameters on which the service is being offered.

Information About Quality of Service on an EVC

EVC Quality of Service and the MQC

QoS functionality is typically applied using traffic classes, class maps, and policy-maps. For example, you can specify that traffic belonging to a particular class be grouped into specific categories, and receive a specific QoS treatment (such as classification or policing). The QoS treatment the traffic is to receive is specified in a policy-map and the policy-map is attached to an interface. The mechanism used for applying QoS in this manner is the modular QoS CLI (MQC.)

The policy-map can be attached to an interface in either the incoming (ingress) or outgoing (egress) direction with the service-policy command.

The MQC structure allows you to define a traffic class, create a traffic policy, and attach the traffic policy to an interface (in this case, an EVC).

The MQC structure consists of the following three high-level steps.

  1. Define a traffic class by using the class-map command. A traffic class is used to classify traffic.

  2. Create a traffic policy by using the policy-map command. (The terms traffic policy and policy-map are often synonymous.) A traffic policy (policy-map) contains a traffic class and one or more QoS features that will be applied to the traffic class. The QoS features in the traffic policy determine how to treat the classified traffic.

  3. Attach the traffic policy (policy-map) to the interface by using the service-policy command.


Note

For more information about the MQC, including information about hierarchical policy-maps and class maps, see the "Applying QoS Features Using the MQC" module.

QoS-Aware Ethernet Flow Point (EFP)

As described in the EVC Quality of Service and the MQC , the MQC is used to apply one or more QoS features to network traffic. The last step in using the MQC is to attach the traffic policy (policy-map) to an interface (in this case, an EVC) by using the service-policy command.

With the EVC Quality of Service feature, the service-policy command can be used to attach the policy-map to an Ethernet Flow Point (EFP) in either the incoming (ingress) or outgoing (egress) direction of an EVC. This way, the EFP is considered to be "QoS-aware."

QoS Functionality and EVCs

The specific QoS functionality includes the following:

  • Packet classification (for example, based on differentiated services code point (DSCP) value and QoS group identifier)

  • Packet marking (for example, based on Class of Service (CoS) value)

  • Traffic policing (two- and three-color and multiple actions)

  • Bandwidth sharing

  • Priority queueing (in the outbound direction on the EVC only)

  • Weighted Random Early Detection (WRED)

The QoS functionality is enabled by using the appropriate commands listed in the following sections.

match Commands Supported by EVC QoS for Classifying Traffic

The table below lists some of the available match commands that can be used when classifying traffic on an EVC. The available match commands vary by Cisco IOS XE release. For more information about the commands and command syntax, see the Cisco IOS Quality of Service Solutions Command Reference.

Table 1. match Commands That Can Be Used with the MQC

Command

Purpose

match access-group

Configures the match criteria for a class map on the basis of the specified access control list (ACL).

match any

Configures the match criteria for all packets.

match cos

Matches a packet based on a Layer 2 CoS marking.

match cos inner

Matches the inner CoS of QinQ packets on a Layer 2 CoS marking.

match [ip ] dscp

Identifies a specific IP DSCP value as a match criterion. Up to eight DSCP values can be included in one match statement.

match not

Specifies the single match criterion value to use as an unsuccessful match criterion.

Note

 

The match not command, rather than identifying the specific match parameter to use as a match criterion, is used to specify a match criterion that prevents a packet from being classified as a member of the class. For instance, if the match not qos-group 6 command is issued while you configure the traffic class, QoS group 6 becomes the only QoS group value that is not considered a successful match criterion. All other QoS group values would be successful match criteria.

match [ip ] precedence

Identifies IP precedence values as match criteria.

match qos-group

Identifies a specific QoS group value as a match criterion.

match source-address mac

Uses the source MAC address as a match criterion.

Note

 

Classifying traffic using the match source-address mac command is supported in the input direction only.

match vlan (QoS)

Matches and classifies traffic on the basis of the VLAN identification number.

match vlan inner

Configures a class map to match the innermost VLAN ID in an 802.1q tagged frame.

Multiple match Commands in One Traffic Class

If the traffic class contains more than one match command, you need to specify how to evaluate the match commands. You specify this by using either the match-any or match-all keyword of the class-map command. Note the following points about the match-any and match-all keywords:

  • If you specify the match-any keyword, the traffic being evaluated by the traffic class must match one of the specified criteria.

  • If you specify the match-all keyword, the traffic being evaluated by the traffic class must match all of the specified criteria.

  • If you do not specify either keyword, the traffic being evaluated by the traffic class must match all of the specified criteria (that is, the behavior of the match-all keyword is used).

Commands Used to Enable QoS Features on the EVC

The commands used to enable QoS features vary by Cisco IOS XE release. The table below lists some of the available commands and the QoS features that they enable. For complete command syntax, see the Cisco IOS Quality of Service Solutions Command Reference.

For more information about a specific QoS feature that you want to enable, see the appropriate module of the Cisco IOS Quality of Service Solutions Configuration Guide.

Table 2. Commands Used to Enable QoS Features

Command

Purpose

bandwidth

Configures a minimum bandwidth guarantee for a class.

bandwidth remaining

Configures an excess weight for a class.

drop

Discards the packets in the specified traffic class.

fair-queue

Enables the flow-based queueing feature within a traffic class.

police

Configures traffic policing. Allows specifying of multiple policing actions.

police (percent)

Configures traffic policing on the basis of a percentage of bandwidth available on an interface.

police (two rates)

Configures traffic policing using two rates, the committed information rate (CIR) and the peak information rate (PIR).

priority

Gives priority to a class of traffic belonging to a policy-map.

queue-limit

Specifies or modifies the maximum number of packets the queue can hold for a class configured in a policy-map.

random-detect

Enables Weighted Random Early Detection (WRED).

random-detect cos-based

Enables Weighted random early detection (WRED) on the basis of the class of service (CoS) value of a packet.

random-detect dscp-based

Specifies that Weighted random early detection (WRED) is to use the differentiated services code point (DSCP) value when it calculates the drop probability for a packet.

random-detect discard-class

Configures the WRED parameters for a discard-class value for a class in a policy-map.

random-detect discard-class-based

Configures WRED on the basis of the discard class value of a packet.

random-detect exponential-weighting-constant

Configures the exponential weight factor for the average queue size calculation for the queue reserved for a class.

random-detect precedence

Configure the WRED parameters for a particular IP Precedence for a class policy in a policy-map.

service-policy

Specifies the name of a traffic policy used as a matching criterion (for nesting traffic policies [hierarchical traffic policies] within one another).

set cos

Sets the Layer 2 CoS value of an outgoing packet.

set cos-inner

Marks the inner class of service field in a bridged frame.

set discard-class

Marks a packet with a discard-class value.

set [ip ] dscp

Marks a packet by setting the DSCP value in the type of service (ToS) byte.

set mpls experimental

Designates the value to which the Multiprotocol Label Switching (MPLS) bits are set if the packets match the specified policy-map.

set precedence

Sets the precedence value in the packet header.

set qos-group

Sets a QoS group identifier (ID) that can be used later to classify packets.

shape

Shapes traffic to the indicated bit rate according to the algorithm specified.

input and output Keywords of the service-policy Command

As a general rule, the QoS features configured in the traffic policy can be applied to packets entering the interface or to packets leaving the interface. Therefore, when you use the service-policy command, you need to specify the direction of the traffic policy by using the input or output keyword.

For instance, the service-policy output policy-map1 command would apply the QoS features in the traffic policy to the interface in the output direction. All packets leaving the interface (output) are evaluated according to the criteria specified in the traffic policy named policy-map1.


Note

For Cisco releases, queueing mechanisms are not supported in the input direction. Nonqueueing mechanisms (such as traffic policing and traffic marking) are supported in the input direction. Also, classifying traffic on the basis of the source MAC address (using the match source-address mac command) is supported in the input direction only.

How to Configure a Quality of Service Feature on an EVC

Creating a Traffic Class for Use on the EVC

To create a traffic class, use the class-map command to specify the traffic class name. Then use one or more match commands to specify the appropriate match criteria. Packets matching the criteria that you specify are placed in the traffic class.

To create the traffic class for use on the EVC, complete the following steps.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. class-map [match-all | match-any ] class-name
  4. match cos cos-number
  5. Enter additional match commands, if applicable; otherwise, proceed with the next step.
  6. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

class-map [match-all | match-any ] class-name

Example:


Router(config)# class-map match-any class1

Creates a class map and enters class-map configuration mode.

  • The class map is used for matching packets to the specified class.

Note

 

The match-all keyword specifies that all match criteria must be met. The match-any keyword specifies that one of the match criteria must be met. Use these keywords only if you will be specifying more than one match command.

Step 4

match cos cos-number

Example:


Router(config-cmap)# match cos 2

Matches a packet on the basis of a Layer 2 CoS number.

Note

 

The match cos command is an example of a match command you can use.

Step 5

Enter additional match commands, if applicable; otherwise, proceed with the next step.

--

Step 6

end

Example:


Router(config-cmap)# end

(Optional) Exits class map configuration mode and returns to privileged EXEC mode.

Creating a Policy-Map for Use on the EVC

To create a traffic policy (or policy-map) for use on the EVC, complete the following steps.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. policy-map policy-map-name
  4. class {class-name | class-default }
  5. police bps [burst-normal ] [burst-max ] [conform-action action ] [exceed-action action ] [violate-action action ]
  6. Enter the commands for any additional QoS feature that you want to enable, if applicable; otherwise, proceed to the next step.
  7. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

policy-map policy-map-name

Example:


Router(config)#
 
policy-map policy1

Creates or specifies the name of the traffic policy and enters QoS policy-map configuration mode.

Step 4

class {class-name | class-default }

Example:


Router(config-pmap)#
 
class class1

Specifies the name of a class and enters QoS policy-map class configuration mode.

Note

 

This step associates the traffic class with the traffic policy.

Step 5

police bps [burst-normal ] [burst-max ] [conform-action action ] [exceed-action action ] [violate-action action ]

Example:


Router(config-pmap-c)# police 3000

(Optional) Configures traffic policing.

Note

 

The police command is an example of a command that you can use in a policy-map to enable a QoS feature.

Step 6

Enter the commands for any additional QoS feature that you want to enable, if applicable; otherwise, proceed to the next step.

--

Step 7

end

Example:


Router(config-pmap-c)# end

(Optional) Exits QoS policy-map class configuration mode and returns to privileged EXEC mode.

Configuring the EVC and Attaching a Traffic Policy to the EVC

The traffic policy (policy-map) applies the enabled QoS feature to the traffic class once you attach the policy-map to the EVC.

To configure the EVC and attach a traffic policy to the EVC, complete the following steps.


Note

One of the commands used to attach the traffic policy to the EVC is the service-policy command. When you use this command, you must specify either the input or output keyword along with the policy-map name. The policy-map contains the QoS feature you want to use. Certain QoS features can only be used in either the input or output direction. For more information about these keywords and the QoS features supported, see the input and output Keywords of the service-policy Command. Also, if you attach a traffic policy to an interface containing multiple EVCs, the traffic policy will be attached to all of the EVCs on the interface.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. interface interface-type interface-number
  4. service instance id ethernet [evc-nam e]
  5. encapsulation dot1q vlan-id [,vlan-id [-vlan-id ]] [native ]
  6. rewrite ingress tag translate 1-to-1 dot1q vlan-id symmetric
  7. bridge domain domain-number
  8. service-policy {input | output } policy-map-name
  9. end
  10. show policy-map interface type number service instance service-instance-number

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

interface interface-type interface-number

Example:


Router(config)# interface gigabitethernet 0/0/1

Configures an interface type and enters interface configuration mode.

  • Enter the interface type and interface number.

Step 4

service instance id ethernet [evc-nam e]

Example:


Router(config-if)# service instance 333 ethernet evc1

Configures an Ethernet service instance on an interface and enters Ethernet service configuration mode.

  • Enter the service instance identification number and, if applicable, the EVC name (optional).

Step 5

encapsulation dot1q vlan-id [,vlan-id [-vlan-id ]] [native ]

Example:


Router(config-if-srv)# encapsulation dot1q 10

Defines the matching criteria to map 802.1Q frames ingress on an interface to the appropriate service instance.

Step 6

rewrite ingress tag translate 1-to-1 dot1q vlan-id symmetric

Example:


Router(config-if-srv)# rewrite ingress tag translate 1-to-1 dot1q 300 symmetric

Specifies the encapsulation adjustment to be performed on a frame ingressing a service instance.

Step 7

bridge domain domain-number

Example:


Router(config-if-srv)# bridge domain 1

Configures a bridge domain.

  • Enter the bridge domain number.

Step 8

service-policy {input | output } policy-map-name

Example:


Router(config-if-srv)#
 
service-policy input policy1

Attaches a policy-map to an interface.

  • Enter either the input or output keyword and the policy-map name.

Step 9

end

Example:


Router(config-if-srv)# end

(Optional) Returns to privileged EXEC mode.

Step 10

show policy-map interface type number service instance service-instance-number

Example:


Router# show policy-map interface gigabitethernet 1/0/0 service instance 30

(Optional) Displays the statistics and the configurations of the input and output policies that are attached to an interface.

  • Enter the interface type, interface number, and service instance number.

Configuration Examples for EVC Quality of Service

Example Creating a Traffic Class for Use on the EVC

In this example, traffic with a CoS value of 2 is placed in the traffic class called class1: 


Router> enable 

Router# configure terminal 

Router(config)# class-map match-any class1 

Router(config-cmap)# match cos 2 

Router(config-cmap)# end

Example Creating a Policy-Map for Use on the EVC

In this example, traffic policing has been configured in the policy-map called policy1. Traffic policing is the QoS feature applied to the traffic in class1: 


Router> enable 

Router# configure terminal 

Router(config)#
 policy-map policy1 

Router(config-pmap)#
 class class1  

Router(config-pmap-c)# police 3000  

Router(config-pmap-c)# end

Example Configuring the EVC and Attaching a Traffic Policy to the EVC

In this example, an EVC has been configured and a traffic policy called policy1 has been attached to the EVC: 


Router> enable 

Router# configure terminal 

Router(config)# interface gigabitethernet 0/0/1 

Router(config-if)# service instance 333 ethernet evc1 

Router(config-if-srv)# encapsulation dot1q 10 

Router(config-if-srv)# rewrite ingress tag translate 1-to-1 dot1q 300 symmetric 

Router(config-if-srv)# bridge domain 1 

Router(config-if-srv)# service-policy input policy1  

Router(config-if-srv)# end

Example Verifying the Traffic Class and Traffic Policy Information for the EVC

The following is sample output of the show policy-map interface service instance command. It displays the QoS features configured for and attached to the EFP on the GigabitEthernet interface 1/1/7. 


Router# show policy-map interface gigabitethernet 1/1/7 service instance 10
 GigabitEthernet1/1/7: EFP 10
  Service-policy input: multiaction
    Class-map: c1 (match-all)  
      0 packets, 0 bytes
      5 minute offered rate 0000 bps, drop rate 0000 bps
      Match: ip precedence 3 
      police:
          cir 300000 bps, bc 2000 bytes
        conformed 0 packets, 0 bytes; actions:
          set-prec-transmit 7
          set-qos-transmit 10
        exceeded 0 packets, 0 bytes; actions:
          drop 
        conformed 0000 bps, exceed 0000 bps
    Class-map: class-default (match-any)  
      0 packets, 0 bytes
      5 minute offered rate 0000 bps, drop rate 0000 bps
      Match: any

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

Packet classification

"Classifying Network Traffic" module

Selective Packet Discard

“IPv6 Selective Packet Discard” module

Standards

Standard

Title

No new or modified standards are supported, and support for existing standards has not been modified.

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MIBs

MIB

MIBs Link

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

No new or modified RFCs are supported, and support for existing RFCs has not been modified.

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Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Configuring EVC Quality of Service

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to https://cfnng.cisco.com/. An account on Cisco.com is not required.
Table 3. Feature Information for EVC Quality of Service

Feature Name

Releases

Feature Information

EVC Quality of Service

Cisco IOS XE Release 3.3

Cisco IOS Release 15.5(2)T

This document contains information about how to enable quality of service (QoS) features (such as traffic classification and traffic policing) for use on an Ethernet virtual circuit (EVC).

The EVC Quality of Service feature was introduced on the Cisco ASR 1000 Series Aggregation Services Router.

The following commands were introduced or modified: service-policy , show policy-map interface service instance .