Configuring Marking

About Marking

Marking is a method that you use to modify the QoS fields of the incoming and outgoing packets. The QoS fields that you can mark are IP precedence and differentiated services code point (DSCP) in Layer 3. The QoS group is a label local to the system to which you can assign intermediate marking values. You can use the QoS group label to determine the egress scheduling.

You can use marking commands in traffic classes that are referenced in a policy map. The marking features that you can configure are listed in the following table:

Table 1 Configurable Marking Features

Marking Feature

Description

DSCP

Layer 3 DSCP.

IP precedence

Layer 3 IP precedence.

Note   

IP precedence uses only the lower three bits of the type of service (ToS) field. The device overwrites the first three bits of the ToS field to 0.

QoS group

Locally significant QoS values that can be manipulated and matched within the system. The range is from 0 to 3.

Ingress

Status of the marking applies to incoming packets.

CoS

Layer 2 VLAN ID

Licensing Requirements for Marking

The following table shows the licensing requirements for this feature:

Product

License Requirement

Cisco NX-OS

The QoS feature does not a require license. Any feature not included in a license package is bundled with the NX-OS image and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.

Prerequisites for Marking

Classification has the following prerequisites:

  • You must be familiar with using modular QoS CLI.

  • You are logged on to the device.

Guidelines and Limitations

Marking has the following configuration guidelines and limitations:

  • The set qos-group command can only be used in ingress policies.

  • FEX host interfaces (HIF) are supported by the FEX QoS policy.

    • QoS TCAM carving is supported on ALE (Application Leaf Engine) enabled switches.

    • The FEX QoS policy supports only the set qos-group command. Other marking commands are not supported.


      Note

      set qos-group 0 is reserved for class default. It cannot be configured in user defined classes.

    • Match on QoS-group is supported.

  • Interface level egress QoS policies must be applied on 100G ports for egress packet scheduling.

  • When egress QoS policies are not specifically configured for a 100G port, all egress packet traffic goes through the default queue (Qos-group 0).

Configuring Marking

You can combine one or more of the marking features in a policy map to control the setting of QoS values. You can then apply policies to either incoming or outgoing packets on an interface.


Note

Do not press Enter after you use the set command and before you add the rest of the command. If you press Enter directly after entering the set keyword, you will be unable to continue to configure with the QoS configuration.

Configuring DSCP Marking

You can set the DSCP value in the six most significant bits of the DiffServ field of the IP header to a specified value. You can enter numeric values from 0 to 60, in addition to the standard DSCP values shown in the following table.

Table 2 Standard DSCP Values

Value

List of DSCP Values

af11

AF11 dscp (001010)—decimal value 10

af12

AF12 dscp (001100)—decimal value 12

af13

AF13 dscp (001110)—decimal value 14

af21

AF21 dscp (010010)—decimal value 18

af22

AF22 dscp (010100)—decimal value 20

af23

AF23 dscp (010110)—decimal value 22

af31

AF31 dscp (011010)—decimal value 26

af32

AF40 dscp (011100)—decimal value 28

af33

AF33 dscp (011110)—decimal value 30

af41

AF41 dscp (100010)—decimal value 34

af42

AF42 dscp (100100)—decimal value 36

af43

AF43 dscp (100110)—decimal value 38

cs1

CS1 (precedence 1) dscp (001000)—decimal value 8

cs2

CS2 (precedence 2) dscp (010000)—decimal value 16

cs3

CS3 (precedence 3) dscp (011000)—decimal value 24

cs4

CS4 (precedence 4) dscp (100000)—decimal value 32

cs5

CS5 (precedence 5) dscp (101000)—decimal value 40

cs6

CS6 (precedence 6) dscp (110000)—decimal value 48

cs7

CS7 (precedence 7) dscp (111000)—decimal value 56

default

Default dscp (000000)—decimal value 0

ef

EF dscp (101110)—decimal value 46


Note

For more information about DSCP, see RFC 2475.

SUMMARY STEPS

    1.    configure terminal

    2.    policy-map [type qos] [match-first] policy-map-name

    3.    class [type qos] {class-name | class-default} [insert-before before-class-name]

    4.    set dscp dscp-value


DETAILED STEPS
     Command or ActionPurpose
    Step 1configure terminal


    Example: 
    switch# configure terminal
switch(config)#
     

    Enters global configuration mode.

     
    Step 2policy-map [type qos] [match-first] policy-map-name


    Example: 
    switch(config)# policy-map policy1
switch(config-pmap-qos)#
     

    Creates or accesses the policy map named policy-map-name 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 class [type qos] {class-name | class-default} [insert-before before-class-name]


    Example: 
    switch(config-pmap-qos)# class class1
switch(config-pmap-c-qos)#
     

    Creates a reference to class-name and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

     
    Step 4set dscp dscp-value


    Example: 
    switch(config-pmap-c-qos)# set
dscp af31
     

    Sets the DSCP value to dscp-value. Standard values are shown in the previous Standard DSCP Values table.

    When the QoS policy is applied on the VLAN configuration level, the DSCP value derives the CoS value for bridged and routed traffic from the 3 most significant DSCP bits.

     

    This example shows how to display the policy-map configuration: 

    switch# show policy-map policy1

    Configuring IP Precedence Marking

    You can set the value of the IP precedence field in bits 0–2 of the IPv4 type of service (ToS) field of the IP header.


    Note

    The device rewrites the last 3 bits of the ToS field to 0 for packets that match this class.

    Table 3 Precedence Values

    Value

    List of Precedence Values

    0-7

    IP precedence value

    critical

    Critical precedence (5)

    flash

    Flash precedence (3)

    flash-override

    Flash override precedence (4)

    immediate

    Immediate precedence (2)

    internet

    Internetwork control precedence (6)

    network

    Network control precedence (7)

    priority

    Priority precedence (1)

    routine

    Routine precedence (0)

    SUMMARY STEPS

      1.    configure terminal

      2.    policy-map [type qos] [match-first] policy-map-name

      3.    class [type qos] {class-name | class-default} [insert-before before-class-name]

      4.    set precedence precedence-value


    DETAILED STEPS
       Command or ActionPurpose
      Step 1configure terminal


      Example: 
      switch# configure terminal
switch(config)#
       

      Enters global configuration mode.

       
      Step 2policy-map [type qos] [match-first] policy-map-name


      Example: 
      switch(config)# policy-map policy1
switch(config-pmap-qos)#
       

      Creates or accesses the policy map named policy-map-name 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 class [type qos] {class-name | class-default} [insert-before before-class-name]


      Example: 
      switch(config-pmap-qos)# class class1
switch(config-pmap-c-qos)#
       

      Creates a reference to class-name and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before.

       
      Step 4 set precedence precedence-value


      Example: 
      switch(config-pmap-c-qos)# set precedence 3
       

      Sets the IP precedence value to precedence-value. The value can range from 0 to 7. You can enter one of the values shown in the above Precedence Values table.

       

      This example shows how to display the policy-map configuration: 

      switch# show policy-map policy1

      Configuring CoS Marking

      You can set the value of the CoS field in the high-order three bits of the VLAN ID Tag field in the IEEE 802.1Q header.

      SUMMARY STEPS

        1.    configure terminal

        2.    policy-map [type qos] [match-first] [qos-policy-map-name | qos-dynamic]

        3.    class [type qos] {class-map-name | class-default} [insert-before before-class-name]

        4.    set cos cos-value


      DETAILED STEPS
         Command or ActionPurpose
        Step 1configure terminal


        Example: 
        switch# configure terminal
switch(config)#
         

        Enters global configuration mode.

         
        Step 2policy-map [type qos] [match-first] [qos-policy-map-name | qos-dynamic]


        Example: 
        switch(config)# policy-map policy1
switch(config-pmap-qos)#
         

        Creates or accesses the policy map named qos-policy-map-name, 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 class [type qos] {class-map-name | class-default} [insert-before before-class-name]


        Example: 
        switch(config-pmap-qos)# class class1
switch(config-pmap-c-qos)#
         

        Creates a reference to class-map-name, and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

         
        Step 4 set cos cos-value


        Example: 
        switch(config-pmap-c-qos)# set cos 3
switch(config-pmap-c-qos)#
         

        Sets the CoS value to cos-value. The value can range from 0 to 7.

         

        This example shows how to display the policy-map configuration: 

        switch# show policy-map policy1

        Configuring CoS Marking for FEX

        You can mark traffic based on the class of service (CoS) for a FEX.

        Before You Begin

        Before configuring the FEX, enable feature-set fex.

        SUMMARY STEPS

          1.    configure terminal

          2.    policy-map [type qos] [match-first] [qos-policy-map-name | qos-dynamic]

          3.    class [type qos] {class-map-name | class-default} [insert-before before-class-name]


        DETAILED STEPS
           Command or ActionPurpose
          Step 1configure terminal


          Example: 
          switch# configure terminal
switch(config)#
           

          Enters global configuration mode.

           
          Step 2policy-map [type qos] [match-first] [qos-policy-map-name | qos-dynamic]


          Example: 
          switch(config)# policy-map policy1
switch(config-pmap-qos)#
           

          Creates or accesses the policy map named qos-policy-map-name, 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 class [type qos] {class-map-name | class-default} [insert-before before-class-name]


          Example: 
          switch(config-pmap-qos)# class class1
switch(config-pmap-c-qos)#
           

          Creates a reference to class-map-name, and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

           

          This example shows how to configure the CoS class-map configuration: 

          switch# conf t
switch(config)# policy-map type qos setpol
switch(config-pmap-qos)# class  cos6
switch(config-pmap-c-qos)# set qos-group 3
switch(config-pmap-qos)# class  cos3
switch(config-pmap-c-qos)# set qos-group 2
switch(config-pmap-qos)# class  cos1
switch(config-pmap-c-qos)# set qos-group 1
switch(config-pmap-qos)# class class-default

          Configuring Ingress Marking

          You can apply the marking instructions in a QoS policy map to ingress packets by attaching that QoS policy map to an interface. To select ingress, you specify the input keyword in the service-policy command.

          For more information, see the “Attaching and Detaching a QoS Policy Action” section.

          Configuring DSCP Port Marking

          You can set the DSCP value for each class of traffic defined in a specified ingress policy map.

          The default behavior of the device is to preserve the DSCP value or to trust DSCP. To make the port untrusted, change the DSCP value. Unless you configure a QoS policy and attach that policy to specified interfaces, the DSCP value is preserved.


          Note

          • You can attach only one policy type qos map to each interface in each direction.

          • The DSCP value is trust on the Layer 3 port of a Cisco NX-OS device.

          SUMMARY STEPS

            1.    configure terminal

            2.    policy-map [type qos] [match-first] [policy-map-name]

            3.    class [type qos] {class-name | class-default} [insert-before before-class-name]

            4.    set dscp-value

            5.    exit

            6.    class [type qos] {class-name | class-default} [insert-before before-class-name]

            7.    set dscp-value

            8.    exit

            9.    class [type qos] {class-name | class-default} [insert-before before-class-name]

            10.    set dscp-value

            11.    exit

            12.    interface ethernet slot/port

            13.    service-policy [type qos] {input | output} {policy-map-name} [no-stats]


          DETAILED STEPS
             Command or ActionPurpose
            Step 1configure terminal


            Example: 
            switch# configure terminal
switch(config)#
             

            Enters global configuration mode.

             
            Step 2policy-map [type qos] [match-first] [policy-map-name]


            Example: 
            switch(config)# policy-map policy1
switch(config-pmap-qos)#
             

            Creates or accesses the policy map named policy-map-name 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 class [type qos] {class-name | class-default} [insert-before before-class-name]


            Example: 
            switch(config-pmap-qos)# class class1
switch(config-pmap-c-qos)#
             

            Creates a reference to class-name and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

             
            Step 4 set dscp-value


            Example: 
            switch(config-pmap-c-qos)# set dscp af31
             

            Sets the DSCP value to dscp-value. Valid values are listed in the Standard DSCP Values table in the Configuring DSCP Marking section.

             
            Step 5 exit


            Example: 
            switch(config-pmap-c-qos)# exit
switch(config-pmap-qos)#
             

            Returns to policy-map configuration mode.

             
            Step 6 class [type qos] {class-name | class-default} [insert-before before-class-name]


            Example: 
            switch(config-pmap-qos)# class class2
switch(config-pmap-c-qos)#
             

            Creates a reference to class-name and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

             
            Step 7 set dscp-value


            Example: 
            switch(config-pmap-c-qos)# set dscp af1
             

            Sets the DSCP value to dscp-value. Valid values are listed in the Standard DSCP Values table in the Configuring DSCP Marking section.

             
            Step 8 exit


            Example: 
            switch(config-pmap-c-qos)# exit
switch(config-pmap-qos)#
             

            Returns to policy-map configuration mode.

             
            Step 9 class [type qos] {class-name | class-default} [insert-before before-class-name]


            Example: 
            switch(config-pmap-qos)# class class-default
switch(config-pmap-c-qos)#
             

            Creates a reference to class-name and enters policy-map class configuration mode. The class is added to the end of the policy map unless insert-before is used to specify the class to insert before. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map.

             
            Step 10 set dscp-value


            Example: 
            switch(config-pmap-c-qos)# set dscp af22
switch(config-pmap-c-qos)#
             

            Sets the DSCP value to dscp-value. Valid values are listed in the Standard DSCP Values table in the Configuring DSCP Marking section.

             
            Step 11 exit


            Example: 
            switch(config-pmap-c-qos)# exit
switch(config-pmap-qos)#
             

            Returns to policy-map configuration mode.

             
            Step 12interface ethernet slot/port


            Example: 
            switch(config)# interface ethernet 1/1
switch(config-if)#
             

            Enters interface mode to configure the Ethernet interface.

             
            Step 13service-policy [type qos] {input | output} {policy-map-name} [no-stats]


            Example: 
            switch(config-if)# service-policy input policy1
             

            Adds policy-map-name to the input packets of the interface. You can attach only one input policy and one output policy to an interface.

             

            This example shows how to display the policy-map configuration: 

            switch# show policy-map policy1

            Verifying the Marking Configuration

            To display the marking configuration information, perform one of the following tasks:

            Command

            Purpose

            show policy-map

            Displays all policy maps.

            Configuration Examples for Marking

            The following example shows how to configure marking: 

            configure terminal
policy-map type qos untrust_dcsp
class class-default
set precedence 3
set qos-qroup 3
set dscp 0