ATM Multilink PPP Support on Multiple VCs

The ATM Multilink PPP Support on Multiple VCs feature facilitates traffic load balancing on high-speed virtual circuits (VCs) using multilink PPP (MLP) over Frame Relay and ATM. It also facilitates traffic load balancing by using MLP to combine packet datagrams on high-speed VCs as a means of transporting both the voice and data traffic more efficiently.

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.

Restrictions for ATM Multilink PPP Support

The ATM Multilink PPP Support on Multiple VCs feature does not support the following commands and functionality. The configuration accepts these commands, but the commands have no effect:

  • ppp interleave

  • ppp multilink fragment-delay

The ATM Multilink PPP Support on Multiple VCs feature does not support the link fragmentation and interleaving (LFI) functionality.

Information About ATM Multilink PPP Support

ATM Multilink PPP Support Overview

Load balancing operates at Layer 2 or Layer 3 (the network layer) of the Open System Interconnection (OSI) reference model. Layer 3 load balancing is independent of any link-layer technologies. The ATM Multilink Point-to-Point Protocol (PPP) Support on Multiple VCs feature implements load balancing at Layer 2 and depends on having MLP enabled at the link layer.

The ATM MLP functionality keeps track of packet sequencing, and this functionality buffers any packets that arrive early. With this ability, ATM MLP preserves packet order across the entire bundle.

In addition to MLP, low latency queueing (LLQ) and class-based weighted fair queueing (CBWFQ) are used to prioritize and differentiate the voice and data packets. LLQ and CBWFQ help to ensure that the voice and data traffic receive the proper quality of service (QoS) treatment (such as the correct priority queue assignment) when the voice and data traffic are transmitted.

For more information about LLQ and CBWFQ, see the Cisco IOS Quality of Service Solutions Configuration Guide.

Benefits of ATM Multilink PPP Support

Facilitates More Efficient Traffic Load Balancing

The ATM Multilink PPP Support on Multiple VCs feature supports the transport of real-time (voice) and other (data) traffic on Frame Relay and ATM VCs.

How to Configure ATM Multilink PPP Support

Defining the Service Policy Using the MQC

Perform this task to define the service policy using the MQC. The MQC allows you to create class maps and define service policies. Service policies are used to create classes and set match criteria for classifying traffic.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

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

    4.    match ip precedence ip-precedence-value [ip-precedence-value ip-precedence-value ip-precedence-value]

    5.    exit

    6.    policy-map policy-name

    7.    class-map class-map-name [match-all| match-any

    8.    bandwidth {bandwidth-kbps | percent percent}

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


    Example:
    Router(config)# class-map class1
     

    Specifies the name of the class map to be created and enters class-map configuration mode. If match-all or match-any value is not specified, traffic must match all the match criteria to be classified as part of the class map.

     
    Step 4 match ip precedence ip-precedence-value [ip-precedence-value ip-precedence-value ip-precedence-value]


    Example:
    Router(config-cmap)# match ip precedence 3 2 4
     

    Identifies IP precedence values as match criteria.

     
    Step 5 exit


    Example:
    Router(config-cmap)# exit
     

    Exits class-map configuration mode.

     
    Step 6 policy-map policy-name


    Example:
    Router(config)# policy-map policy1
     

    Specifies the name of the policy map to be created and enters policy-map configuration mode.

     
    Step 7 class-map class-map-name [match-all| match-any


    Example:
    Router(config-pmp)# class class2
     

    Classifies traffic based on the class map specified and enters policy-map class configuration mode.

     
    Step 8 bandwidth {bandwidth-kbps | percent percent}


    Example:
    Router (config-pmap-c)# bandwidth 45
     

    Specifies a minimum bandwidth guarantee to a traffic class in periods of congestion.

    • A minimum bandwidth guarantee can be specified in kbps or by a percentage of the overall available bandwidth.

     
    Step 9 end


    Example:
    Router(config-pmp)# end
     

    Exits class-map configuration mode.

     

    Defining a Multilink MLP Bundle Interface

    Perform this task to define a multilink MLP bundle interface. The purpose of a multilink bundle interface is to combine more than one permanent virtual circuit (PVC). All configurations for PPP over ATM links are placed into virtual templates, and the bundle parameters are placed into the multilink bundle.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type number

      4.    ip address ip-address mask [secondary]

      5.    load-interval seconds

      6.    no cdp enable

      7.    service-policy output policy-name

      8.    ppp multilink

      9.    ppp multilink fragment disable

      10.    ppp multilink group group-number

      11.    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 interface type number


      Example:
      Router(config)# interface multilink 34
       

      Configures an interface type and enters interface configuration mode.

       
      Step 4 ip address ip-address mask [secondary]


      Example:
      Router(config-if)# ip address 209.165.201.1 255.255.255.0
       

      Sets a primary or secondary IP address for an interface.

       
      Step 5 load-interval seconds


      Example:
      Router(config-if)# load-interval 60
       

      Changes the length of time for which data is used to compute load statistics.

       
      Step 6 no cdp enable


      Example:
      Router(config-if)# no cdp enable
       

      Disables Cisco Discovery Protocol (CDP) on an interface.

       
      Step 7 service-policy output policy-name


      Example:
      Router(config-if)# service-policy output policy1
       

      Attaches the specified policy map to the output interface.

       
      Step 8 ppp multilink


      Example:
      Router(config-if)# ppp multilink
       

      Enables MLP on an interface.

       
      Step 9 ppp multilink fragment disable


      Example:
      Router(config-if)# ppp multilink fragment disable
       

      Disables packet fragmentation.

       
      Step 10 ppp multilink group group-number


      Example:
      Router(config-if)# ppp multilink group 54
       

      Restricts a physical link to joining only a designated multilink-group interface.

       
      Step 11 end


      Example:
      Router(config-if)# end
       

      Exits interface configuration mode.

       

      Defining the Virtual Templates for Member Links

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    interface type number

        4.    no ip address

        5.    load-interval seconds

        6.    ppp multilink

        7.    ppp multilink group group-number

        8.    end


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example: 
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.

         
        Step 2 configure terminal


        Example: 
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3 interface type number


        Example: 
        Device(config)# interface multilink 34
         

        Configures an interface type and enters interface configuration mode.

         
        Step 4 no ip address


        Example: 
        Device(config-if)# no ip address
         

        Removes existing IP addresses or disables IP processing.

         
        Step 5 load-interval seconds


        Example: 
        Device(config-if)# load-interval 30
         

        Changes the length of time for which data is used to compute load statistics.

         
        Step 6 ppp multilink


        Example: 
        Device(config-if)# ppp multilink
         

        Enables MLP on the interface.

         
        Step 7 ppp multilink group group-number


        Example: 
        Device(config-if)# ppp multilink-group 44
         

        Restricts a physical link to joining only a designated multilink-group interface.

         
        Step 8 end


        Example: 
        Device(config-if)#
 
end
         

        Exits interface configuration mode.

         

        Defining the PVCs and Bundling Member Links

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    Do one of the following:

          • interface atm slot /0
          • interface atm slot / port

          4.    no ip address

          5.    load interval seconds

          6.    atm ilmi-keepalive [seconds [retry[seconds]]]

          7.    pvc [name ] vpi/vci

          8.    vbr-nrt output-pcr output-scr [output-mbs ]

          9.    tx-ring-limit ring-limit

          10.    protocol ppp virtual-template number

          11.    end


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 enable


          Example: 
          Device> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.

           
          Step 2 configure terminal


          Example: 
          Device# configure terminal
           

          Enters global configuration mode.

           
          Step 3Do one of the following:
          • interface atm slot /0
          • interface atm slot / port


          Example: 
          Device(config)# interface atm 2/0


          Example: 
          or


          Example: 
          Device(config)# interface atm 2/1
           

          Specifies the ATM interface type and enters interface configuration mode.

           
          Step 4 no ip address


          Example: 
          Device(config-if)# no ip address
           

          Removes an IP address or disables IP processing.

           
          Step 5 load interval seconds


          Example: 
          Device(config-if)# load interval 30
           

          Changes the length of time for which data is used to compute load statistics.

           
          Step 6 atm ilmi-keepalive [seconds [retry[seconds]]]


          Example: 
          Device(config-if)# atm ilmi-keepalive
           

          Enables Interim Local Management Interface (ILMI) keepalives.

           
          Step 7 pvc [name ] vpi/vci


          Example: 
          Device(config-if)# pvc pvc1 0/56
           

          Creates an ATM PVC. Enters interface-ATM-VC configuration mode.

           
          Step 8 vbr-nrt output-pcr output-scr [output-mbs ]


          Example: 
          Device(config-if-atm-vc)# vbr-nrt 45 4 45
           

          Configures the variable bit rate (VBR)-non real time (NRT) QoS and specifies output peak cell rate, output sustainable cell rate, and output maximum burst cell size.

           
          Step 9 tx-ring-limit ring-limit


          Example: 
          Device(config-if-atm-vc)# tx-ring-limit 3
           

          Limits the number of particles or packets that can be used on a transmission ring on an interface.

          • Use this command to tune the transmission ring to assign most of the packets to the Layer 3 queues.

           
          Step 10 protocol ppp virtual-template number


          Example: 
          Device(config-if-atm-vc)# protocol ppp virtual-template 34
           

          Specifies that PPP is established over the ATM PVC using the configuration from the specified virtual template and enters interface configuration mode.

           
          Step 11 end


          Example: 
          Device(config-if)# end
           

          Exits interface configuration mode.

           

          Verifying ATM Multilink PPP Support

          Perform this task to display information about ATM Multilink PPP Support on Multiple VCs:

          SUMMARY STEPS

            1.    enable

            2.    show atm pvc

            3.    show frame-relay pvc [[interface interface] [dlci] [64-bit] | summary [all]]

            4.    show interfaces

            5.    show policy-map

            6.    show ppp multilink

            7.    show queueing


          DETAILED STEPS
             Command or ActionPurpose
            Step 1 enable


            Example: 
            Device> enable
             

            Enables privileged EXEC mode.

            • Enter your password if prompted.

             
            Step 2 show atm pvc


            Example: 
            Device# show atm pvc
             

            Displays all ATM PVCs and traffic information.

             
            Step 3 show frame-relay pvc [[interface interface] [dlci] [64-bit] | summary [all]]


            Example: 
            Device# show frame-relay pvc 16
             

            Displays statistics about PVCs for Frame Relay interfaces.

             
            Step 4 show interfaces


            Example: 
            Device# show interfaces
             

            Displays interleaving statistics.

            • Interleaving data is displayed only if interleaving occurs.

             
            Step 5 show policy-map


            Example: 
            Device# show policy-map
             

            Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

             
            Step 6 show ppp multilink


            Example: 
            Device# show ppp multilink
             

            Displays bundle information for the MLP bundles and their PPP links in the Device.

             
            Step 7 show queueing


            Example: 
            Device# show queueing
             

            Lists all or selected configured queueing strategies.

             

            Monitoring ATM Multilink PPP Support

            SUMMARY STEPS

              1.    enable

              2.    debug atm errors

              3.    debug atm events

              4.    debug ppp error

              5.    debug ppp multilink events

              6.    debug voice rtp


            DETAILED STEPS
               Command or ActionPurpose
              Step 1 enable


              Example: 
              Device> enable
               

              Enables privileged EXEC mode.

              • Enter your password if prompted.

               
              Step 2 debug atm errors


              Example: 
              Device# debug atm errors
               

              Displays ATM errors.

               
              Step 3 debug atm events


              Example: 
              Device# debug atm events
               

              Displays ATM events.

               
              Step 4 debug ppp error


              Example: 
              Device# debug ppp error
               

              Displays information on traffic and exchanges in an internetwork implementing the PPP.

               
              Step 5 debug ppp multilink events


              Example: 
              Device# debug ppp multilink events
               

              Displays information about events affecting multilink groups.

               
              Step 6 debug voice rtp


              Example: 
              Device# debug voice RTP
               

              Displays information about the interleaving of voice and data packets.

              • The debug voice RTP command has memory overhead and should not be used when memory is scarce or when traffic is very high.

               

              Configuration Examples for ATM Multilink PPP Support

              Defining the Service Policy Using MQC Example

              The following example shows how to configure a service policy using the MQC: 

              Device> enable
Device# configure terminal
Device(config)# class-map match-all DATA
Device(config-cmap)# match ip precedence 0
Device(config-cmap)# class-map match-all VOICE
Device(config-cmap)# match access-group 100
Device(config-cmap)# policy-map CISCO
Device(config-pmap)# class VOICE
Device(config-pmap-c)# priority percent 70
Device(config-pmap-c)# class DATA
Device(config-pmap-c)# bandwidth percent 5
Device(config-pmap-c)# access-list 100 permit udp any any precedence critical

              Defining a Multilink MLP Bundle Interface Example

              The following example shows how to define a multilink bundle for the mulitilink interface: 

              Device> enable
Device# configure terminal
Device(config)# interface Multilink1
Device(config-if)# ip address 10.2.1.1 255.0.0.0
Device(config-if)# load-interval 30
Device(config-if)# no cdp enable
Device(config-if)# service-policy output CISCO
Device(config-if)# ppp multilink fragment disable
Device(config-if)# ppp multilink group 1

              Defining Virtual Templates for Member Links Example

              The following example shows how to define virtual templates for member links: 

              Device> enable
Device# configure terminal
Device(config)# interface Virtual-Template1
Device(config-if)# no ip address
Device(config-if)# load-interval 30
Device(config-if)# ppp multilink
Device(config-if)# ppp multilink group 1
Device(config-if)# interface Virtual-Template2
Device(config-if)# no ip address
Device(config-if)# load-interval 30
Device(config-if)# ppp multilink
Device(config-if)# ppp multilink group 1

              Defining PVCs and Bundling Member Links Example

              The following example shows how to define and configure PVCs as bundle members: 

              Device> enable
Device# configure terminal
Device(config)# interface atm 6/0
Device(config-if)# no ip address
Device(config-if)# load-interval 30
Device(config-if)# atm ilmi-keepalive
Device(config-if)# pvc 0/34
 
Device(config-if-atm-vc)# vbr-nrt 1536 1536
Device(config-if-atm-vc)# tx-ring-limit 5
Device(config-if-atm-vc)# protocol ppp Virtual-Template1
Device(config-if-atm-vc)# pvc 0/35
 
Device(config-if-atm-vc)# vbr-nrt 800 800
Device(config-if-atm-vc)# tx-ring-limit 3
Device(config-if-atm-vc)# protocol ppp Virtual-Template2
Device(config-if-atm-vc)# pvc 0/36 
Device(config-if-atm-vc)# vbr-nrt 800 400 94
Device(config-if-atm-vc)# tx-ring-limit 5
Device(config-if-atm-vc)# protocol ppp Virtual-Template1
Device(config-if-atm-vc)# pvc 0/37
Device(config-if-atm-vc)# vbr-nrt 800 800
Device(config-if-atm-vc)# tx-ring-limit 3
Device(config-if-atm-vc)# protocol ppp Virtual-Template2
Device(config-if-atm-vc)# end

              Additional References for ATM Multilink PPP Support on Multiple VCs

              The following sections provide references related to the ATM Multilink PPP Support on Multiple VCs feature.

              Related Documents

              Related Topic

              Document Title

              QoS configuration tasks

              Cisco IOS Quality of Service Solutions Configuration Guide

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

              Cisco IOS Quality of Service Solutions Command Reference

              WAN configuration tasks

              Cisco IOS Wide-Area Networking Configuration Guide

              WAN commands: complete command syntax, defaults, command mode, command history, usage guidelines, and examples

              Cisco IOS Wide-Area Networking Command Reference

              Cisco IOS commands

              Cisco IOS Master Commands List, All Releases

              MIBs

              MIB

              MIBs Link

              None

              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

              RFC 1990

              The PPP Multilink Protocol (MP)

              Technical Assistance

              Description

              Link

              The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

              To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

              Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

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

              Feature Information for ATM Multilink PPP Support

              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 1 Feature Information for ATM Multilink PPP Support on Multiple VCs

              Feature Name

              Releases

              Feature Information

              ATM Multilink PPP Support on Multiple VCs

              12.2(28)SB 12.2(13)T 12.2(33)SRE

              Cisco IOS Release XE 3.14S

              The ATM Multilink PPP Support on Multiple VCs feature facilitates traffic load balancing on high-speed virtual circuits, using MLP over Frame Relay and ATM. It facilitates traffic load balancing by using MLP to combine packet datagrams on high-speed VCs, as a means for transporting both the voice and data traffic more efficiently.

              In Cisco IOS Release XE 3.14S, support for the ATM Multilink PPP Support on Multiple VCs feature was added on the 4451-X Integrated Services Router.

              Glossary

              LFI --link fragmentation and interleaving. Method of fragmenting large packets and then queueing the fragments between small packets.

              MLP --multilink PPP.

              QoS --quality of service.

              VC --virtual circuit.