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.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

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-mapcommand. 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 6command 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 maccommand 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-allkeyword of the class-map command. Note the following points about the match-any and match-all keywords:

  • If you specify the match-anykeyword, 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 IOS XE Release 2.1 and later 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 ActionPurpose
    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 ActionPurpose
      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 policecommand 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-name]

        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 ActionPurpose
        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-name]


        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 instancecommand. 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. 
					 
        
 
				          		
 
					 
         -- 
					 
        
 
				          		

        
        

        

        
 
	 
        

        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. 
					 
        
 
				          		
 
					 
         -- 
					 
        
 
				          		

        
        

        

        
 
	 
        

        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 
		  www.cisco.com/​go/​cfn. 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.