ISDN/Dialer Access-Link Support for Broadband Aggregation

The ISDN/Dialer Access-Link Support for Broadband Aggregation feature provides client connectivity to a network through PPP connections by using an ISDN PRI Layer 2 Tunneling Protocol (L2TP) access concentrator (LAC) session over IPv4.

This module describes how to configure the ISDN and dialer access-link support for broadband aggregation.

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.

Prerequisites for ISDN/Dialer Access-Link Support for Broadband Aggregation

  • You must configure a Layer 2 Tunneling Protocol (L2TP) network server (LNS) and enable IPv4 before configuring ISDN support for broadband.

  • Ensure that the ISDN/Dialer Access-Link Support for Broadband Aggregation feature installs correctly by enabling the activation of the adventerprise license upon the next reload. 

    enable
 configure terminal
  license boot level adventerprise
end

Restrictions for ISDN/Dialer Access-Link Support for Broadband Aggregation

  • Only IPv4 PPP sessions inside Layer 2 Tunneling Protocol (L2TP) version 2 tunnels are supported.

  • ISDN termination is not supported on the dialer interface or on the d-channel interface. To achieve PPP termination and aggregation (PTA), the router will need to act as a L2TP Access Concentrator (LAC) and forward incoming ISDN calls to a L2TP Network Server (LNS).

Information About ISDN/Dialer Access-Link Support for Broadband Aggregation

Deployment Model for ISDN/Dialer Access-Link Support for Broadband Aggregation

The ISDN/Dialer Access-Link Support for Broadband Aggregation feature provides support for ISDN and dialer PRI access link to broadband PPP IPv4 sessions at the Layer 2 Tunneling Protocol (L2TP) network server (LNS). These sessions are carried over PPP by the L2TP access concentrator (LAC) using ISDN over IPv4. The sessions are sent from the LAC to the LNS through L2TP tunnels. The LNS terminates the PPP sessions and assigns a network layer address to the client. The client data in the IPv4 packet is then routed to the ISP or a corporate network and forwarded to the final destination. The LNS also performs authentication, authorization, and accounting (AAA) actions on the PPP sessions. The figure below describes the deployment model.

Figure 1. Topology Diagram

How to Configure ISDN/Dialer Access-Link Support for Broadband Aggregation


Note

Before you can configure the ISDN switch type on an interface, you must configure a global ISDN switch type by using the isdn switch-type global configuration command. Because global commands are processed before interface-level commands, the command parser does not accept the isdn switch-type command on an interface unless a switch type is first added globally.

Configuring an L2TP Access Concentrator

Perform this task to configure a virtual private dial-up network (VPDN), a Layer 2 Tunneling Protocol (L2TP) access concentrator (LAC), and an ISDN switch type.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    vpdn enable

    4.    vpdn search-order domain dnis

    5.    vpdn-group group-name

    6.    request-dialin

    7.    protocol l2tp

    8.    domain domain-name

    9.    exit

    10.    initiate-to ip ip-address

    11.    local name host-name

    12.    l2tp tunnel password password

    13.    exit

    14.    isdn switch-type switch-type

    15.    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 vpdn enable


    Example:
    Device(config)# vpdn enable
     

    Enables VPDN on a device.

     
    Step 4 vpdn search-order domain dnis


    Example:
    Device(config)# vpdn search-order domain dnis
     

    Specifies how a network access server (NAS) or a tunnel switch performs VPDN tunnel authorization searches.

     
    Step 5 vpdn-group group-name


    Example:
    Device(config)# vpdn-group group1
     

    Creates and associates a VPDN group with a customer or a VPDN profile and enters VPDN group configuration mode.

     
    Step 6 request-dialin


    Example:
    Device(config-vpdn)# request-dialin
     

    Creates a request-dialin VPDN subgroup that indicates the dialing direction and initiates the tunnel; enters VPDN request-dialin group configuration mode.

     
    Step 7 protocol l2tp


    Example:
    Device(config-vpdn-req-in)# protocol l2tp
     

    Specifies that L2TP is the tunneling protocol used by the VPDN subgroup.

     
    Step 8 domain domain-name


    Example:
    Device(config-vpdn-req-in)# domain xyz.com
     

    Specifies the domain name of users that are to be forwarded to a tunnel server using VPDN.

     
    Step 9 exit


    Example:
    Device(config-vpdn-req-in)# exit
     

    Returns to VPDN group configuration mode.

     
    Step 10 initiate-to ip ip-address


    Example:
    Device(config-vpdn)# initiate-to ip 192.0.2.55
     

    Specifies an IP address that is used for Layer 2 tunneling.

     
    Step 11 local name host-name


    Example:
    Device(config-vpdn)# local name host1
     

    Specifies a local hostname that the tunnel uses to identify itself.

     
    Step 12 l2tp tunnel password password


    Example:
    Device(config-vpdn)# l2tp tunnel password password1
     

    Sets a password that the device uses to authenticate the Layer 2 Tunneling Protocol (L2TP) tunnel.

     
    Step 13 exit


    Example:
    Device(config-vpdn)# exit
     

    Returns to global configuration mode.

     
    Step 14 isdn switch-type switch-type


    Example:
    Device(config)# isdn switch-type primary-4ess
     

    Selects a service provider switch type that accommodates PRI.

    • In this example, the ISDN switch type is primary-4ess.

     
    Step 15 end


    Example:
    Device(config)# end
     

    Returns to privileged EXEC mode.

     

    Configuring a PRI Group

    Perform this task to specify an ISDN switch type and to configure a PRI group.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    isdn switch-type switch-type

      4.    controller {T1 | E1} slot/port

      5.    framing esf

      6.    linecode {ami | b8zs | hdb3}

      7.    cablelength long db-gain-value db-loss-value

      8.    pri-group timeslots timeslot-range

      9.    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 isdn switch-type switch-type


      Example:
      Device(config)# isdn switch-type primary-ni
       

      Selects a service provider switch type that accommodates PRI.

       
      Step 4 controller {T1 | E1} slot/port


      Example:
      Device(config)# controller T1 0/1
       

      Enters controller configuration mode.

       
      Step 5 framing esf


      Example:
      Device(config-controller)# framing esf
       

      Selects the extended super frame (esf) type for the T1 data line.

       
      Step 6 linecode {ami | b8zs | hdb3}


      Example:
      Device(config-controller)# linecode b8zs
       

      Selects the line code type for T1 or E1 lines.

      • Alternate Mark Inversion (AMI) is the default for T1 lines.

      • Bipolar With 8-Bit Substitution (B8ZS) is valid only for the T1 controller.

      • High-Density Bipolar 3 (hdb3) is the default for E1 lines.

       
      Step 7 cablelength long db-gain-value db-loss-value


      Example:
      Device(config-controller)# cablelength long gain36 0db
       

      Increases the pulse of a signal at the receiver and decreases the pulse from the transmitter by using pulse equalization and line build-out for a T1 cable.

       
      Step 8 pri-group timeslots timeslot-range


      Example:
      Device(config-controller)# pri-group timeslots 1-2
       

      Configures the PRI group for the T1 or E1 controller to carry voice traffic.

      • Use a hyphen to indicate a range. Groups of time slot ranges separated by commas (for example: 1-4,8-23) are also accepted.

      • You can configure the PRI group to include all available time slots, or you can configure a select group of time slots for the PRI group.

       
      Step 9 end


      Example:
      Device(config-controller)# end
       

      Returns to privileged EXEC mode.

       

      Configuring a Dialer for an ISDN PRI Interface

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    interface serial controller-number:time-slot

        4.    no ip address

        5.    dialer rotary-group interface-number

        6.    dialer-group group-number

        7.    exit

        8.    isdn switch-type switch-type

        9.    isdn timer timer milliseconds

        10.    isdn skipsend-idverify

        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 3 interface serial controller-number:time-slot


        Example:
        Device(config)# interface serial 0/1/7:23
         

        Specifies a serial interface created on a channelized E1 or channelized T1 controller and enters interface configuration mode.

         
        Step 4 no ip address


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

        Removes an existing IP address or disables IP processing.

         
        Step 5 dialer rotary-group interface-number


        Example:
        Device(config-if)# dialer rotary-group 100
         

        Includes a specified interface in a dialer rotary group.

         
        Step 6 dialer-group group-number


        Example:
        Device(config-if)# dialer-group group1
         

        Controls access by configuring an interface to belong to a specific dialing group.

         
        Step 7 exit


        Example:
        Device(config-if)# exit
         

        Returns to global configuration mode.

         
        Step 8 isdn switch-type switch-type


        Example:
        Device(config)# isdn switch-type primary-4ess
         

        Selects a service provider switch type that accommodates PRI.

         
        Step 9 isdn timer timer milliseconds


        Example:
        Device(config)# isdn timer T321 30000
         

        Identifies and configures an ISDN timer and changes the value of the timer for network, call connect, and disconnect waiting periods.

         
        Step 10 isdn skipsend-idverify


        Example:
        Device(config)# isdn skipsend-idverify
         

        Stops user-side PRI interfaces from sending ID verification information.

         
        Step 11 end


        Example:
        Device(config)# end
         

        Returns to privileged EXEC mode.

         

        Configuring a Dialer Interface by Enabling PPP Authentication

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    interface dialer dialer-rotary-group-number

          4.    no ip address

          5.    encapsulation encapsulation-type

          6.    dialer in-band

          7.    dialer idle-timeout seconds

          8.    dialer-group group-number

          9.    no peer default ip address

          10.    ppp authentication protocol1 [protocol2...] [if-needed | list-name | default | callin | one-time | optional]

          11.    exit

          12.    dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}

          13.    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 dialer dialer-rotary-group-number


          Example:
          Device(config)# interface dialer 100
           

          Defines a dialer rotary group and enters interface configuration mode.

           
          Step 4 no ip address


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

          Removes an existing IP address or disables IP processing.

           
          Step 5 encapsulation encapsulation-type


          Example:
          Device(config-if)# encapsulation ppp
           

          Sets the encapsulation method used by the interface.

           
          Step 6 dialer in-band


          Example:
          Device(config-if)# dialer in-band
           

          Specifies that dial-on-demand routing (DDR) is to be supported.

           
          Step 7 dialer idle-timeout seconds


          Example:
          Device(config-if)# dialer idle-timeout 5000
           

          Specifies the duration of idle time before a call is disconnected.

           
          Step 8 dialer-group group-number


          Example:
          Device(config-if)# dialer-group group1
           

          Controls access by configuring an interface to belong to a specific dialing group.

           
          Step 9 no peer default ip address


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

          Disables a prior peer IP address pooling configuration on an interface or removes the default address from your configuration.

           
          Step 10 ppp authentication protocol1 [protocol2...] [if-needed | list-name | default | callin | one-time | optional]


          Example:
          Device(config-if)# ppp authentication chap callin
           

          Enables at least one PPP authentication protocol and specifies the order in which the protocols are selected on the interface.

           
          Step 11 exit


          Example:
          Device(config-if)# exit
           

          Returns to global configuration mode.

           
          Step 12 dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}


          Example:
          Device(config)# dialer-list dialergroup1 protocol ip permit
           

          Defines a DDR dialer list for dialing by protocol or by a combination of a protocol and a previously defined access list.

           
          Step 13 end


          Example:
          Device(config)# end
           

          Returns to privileged EXEC mode.

           

          Verifying ISDN/Dialer Access-Link Support for Broadband Aggregation

          SUMMARY STEPS

            1.    enable

            2.    show ppp all

            3.    show vpdn


          DETAILED STEPS
            Step 1   enable

            Enables privileged EXEC mode.



            Example:
            Device> enable
            Step 2   show ppp all

            Displays the PPP session information.



            Example:
            Device# show ppp all

Interface/ID OPEN+ Nego* Fail-     Stage    Peer Address    Peer Name
------------ --------------------- -------- --------------- --------------------
Se0/1/0:0    LCP+ CHAP*            Fwded    10.1.1.1         example@example.com
            Step 3   show vpdn

            Displays basic information about all active virtual private dial-up network (VPDN) tunnels.



            Example:
            Device# show vpdn

L2TP Tunnel and Session Information Total tunnels 1 sessions 1
 
LocTunID   RemTunID   Remote Name   State  Remote Address  Sessn L2TP Class/
                                                           Count VPDN Group
46988      29813      o2-lns        est    192.0.2.55        1     1             
 
LocID      RemID      TunID      Username, Intf/         State  Last Chg Uniq ID  
                                 Vcid, Circuit                                 
2300       46414      46988      example@e..., Se0/1/0:0  est    00:00:38 3

            Troubleshooting Tips

            Use the following commands to troubleshoot the ISDN/dialer access-link support for broadband aggregation:

            • debug dialer—Displays debugging information about the packets received on a dialer interface.

            • debug isdn q931—Displays information about call setup and teardown of ISDN network connections (Layer 3) between the local router (user side) and the network.

            • debug ppp authentication—Displays authentication protocol messages, including Challenge Handshake Authentication Protocol (CHAP) packet exchanges and Password Authentication Protocol (PAP) exchanges.

            • debug ppp negotiation—Displays information on traffic and exchanges of PPP packets sent during PPP startup, when PPP options are negotiated.

            Configuration Examples for ISDN/Dialer Access-Link Support for Broadband Aggregation

            Example: Configuring an L2TP Access Concentrator

            The following example shows how to configure the Layer 2 Tunneling Protocol (L2TP) access concentrator (LAC): 

            Device(config)# vpdn enable
Device(config)# vpdn search-order domain dnis
Device(config)# vpdn-group group1
Device(config-vpdn)# request-dialin
Device(config-vpdn-req-in)# protocol l2tp
Device(config-vpdn-req-in)# domain xyz.com
Device(config-vpdn-req-in)# exit
Device(config-vpdn)# initiate-to ip 192.0.2.55
Device(config-vpdn)# local name host1
Device(config-vpdn)# l2tp tunnel password password1
Device(config-vpdn)# exit
Device(config)# isdn switch-type primary-4ess

            Example: Configuring a PRI Group

            The following example shows how to specify the ISDN PRI on the T1 controller for slot 0, port 1, and configures time slots 1 to 2: 

            Device(config)# isdn switch-type primary-ni
Device(config)# controller T1 0/1
Device(config-controller)# framing esf
Device(config-controller)# linecode b8zs
Device(config-controller)# cablelength long gain36 0db
Device(config-controller)# pri-group timeslots 1-2

            Example: Configuring a Dialer for an ISDN PRI Interface

            The following example shows how to specify the dialer profile configuration for an ISDN PRI interface: 

            Device(config)# interface serial 0/1/7:23
Device(config-if)# no ip address
Device(config-if)# dialer rotary-group 100
Device(config-if)# dialer-group group1
Device(config-if)# exit
Device(config)# isdn switch-type primary-4ess
Device(config)# isdn timer T321 30000
Device(config)# isdn skipsend-idverify

            Example: Configuring a Dialer Interface by Enabling PPP Authentication

            Device(config)# interface dialer 100
Device(config-if)# no ip address
Device(config-if)# encapsulation ppp
Device(config-if)# dialer in-band
Device(config-if)# dialer idle-timeout 5000
Device(config-if)# dialer-group group1
Device(config-if)# no peer default ip address
Device(config-if)# ppp authentication chap callin
Device(config-if)# exit
Device(config)# dialer-list dialergroup1 protocol ip permit

            Additional References

            Related Documents

            Related Topic

            Document Title

            Cisco IOS commands

            Cisco IOS Master Command List, All Releases

            Broadband and DSL commands

            Cisco IOS Broadband Access Aggregation and DSL Command Reference

            Dial commands

            Cisco IOS Dial Technologies Command Reference

            VPDN commands

            Cisco IOS VPDN Command Reference

            Broadband and DSL configuration

            Broadband Access Aggregation and DSL Configuration Guide

            Technical support documentation for L2TP

            Layer 2 Tunnel Protocol (L2TP)

            Technical support documentation for PPP

            Point-to-Point Protocol (PPP)

            Standards and RFCs

            Standard/RFC

            Title

            RFC 1661

            Point-to-Point Protocol (PPP)

            RFC 2661

            Layer Two Tunneling Protocol (L2TP)

            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 ISDN/Dialer Access-Link Support for Broadband Aggregation

            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 . An account on Cisco.com is not required.
            Table 1 Feature Information for ISDN/Dialer Access-Link Support for Broadband Aggregation

            Feature Name

            Releases

            Feature Information

            ISDN/Dialer Access-Link Support for Broadband Aggregation

            Cisco IOS XE Release 3.8S

            The ISDN/Dialer Access-Link Support for Broadband Aggregation feature provides client connectivity to a network through PPP by using an ISDN PRI LAC session over IPv4.