ISDN Voice Configuration Guide, Cisco IOS Release 15M&T
Expanded Scope for Cause-Code-Initiated Call-Establishment Retries
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Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

This chapter describes how to implement the Expanded Scope for Cause-Code-Initiated Call Establishment Retries feature. This feature enables a gateway to reattempt calls when a disconnect message is received from the PSTN without maintaining extra dial peers.

Feature History for Expanded Scope for Cause-Code-Initiated Call Establishment Retries

Release

Modification

12.2(15)T

This feature was introduced.

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 Expanded Scope for Cause-Code-Initiated Call Establishment Retries

  • Perform the prerequisites that are listed in the "Prerequisites for Configuring ISDN Voice Interfaces" section.
  • Configure ISDN (trunks) or the Cisco Signaling System 7 (SS7) on the gateway.

Restrictions for Expanded Scope for Cause-Code-Initiated Call Establishment Retries

Restrictions are described in the "Restrictions for Configuring ISDN Voice Interfaces" section. In addition, the following applies:

  • This feature must be used with ISDN Net5 PRI or NI2 PRI switch types.

Information About Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

Before this feature was available, there was no easy way to reattempt most calls when a disconnect was received from the PSTN. Only cause code 44 reattempted a call--and only if multiple dial peers to the same destination were configured.


Note


General information about ISDN voice interfaces is presented in the "Information About ISDN Voice Interfaces" section.


This feature enables you to configure a gateway to reattempt a call when a disconnect message is received from the PSTN. You can configure up to 16 arguments (specifying values from 1 to 127 in each argument) for cause codes.


Note


For a list of cause codes, see ISDN Switch Types, Codes, and Values.


How to Configure Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

Configuring Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

To configure expanded scope for cause-code-initiated call-establishment retries, perform the following steps.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    interface type slot/port

    4.    isdn negotiate-bchan [resend-setup] [cause-codes {cause-code1 [cause-code2...cause-code16]}]

    5.    exit


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Router> enable
     

    Enters privileged EXEC mode. Enter your password when prompted.

     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 interface type slot/port


    Example:
    Router(config)# interface serial 0/4
     

    Configures an interface type and enters interface configuration mode for the specified slot/port.

     
    Step 4 isdn negotiate-bchan [resend-setup] [cause-codes {cause-code1 [cause-code2...cause-code16]}]


    Example:
    Router(interface)# isdn negotiate-bchan resend-setup cause-codes 34 44 63
     

    Enables the router to accept a B channel that is different from the B channel requested in the outgoing call-setup message and specifies the cause codes for which the call is reattempted.

    Note   

    You must have ISDN trunks configured on your router before you can configure the cause codes.

     
    Step 5 exit


    Example:
    Router(interface)# exit
     

    Exits the current mode.

     

    Verifying Expanded Scope for Cause-Code-Initiated Call-Establishment Retries

    To verify expanded scope for cause-code-initiated call-establishment retries, perform the following steps (listed alphabetically).

    SUMMARY STEPS

      1.    show isdn status

      2.    show running-config


    DETAILED STEPS
      Step 1   show isdn status

      Use this command to display the status of all ISDN interfaces, including active layers, timer information, and switch-type settings.

      Step 2   show running-config

      Use this command to display basic router configuration, including cause codes and values entered to verify that the gateway can reattempt disconnect calls received form the PSTN.


      Troubleshooting Tips

      • Use the debug isdn q931 command to display calls that the router has attempted or reattempted.

      Configuration Examples for Expanded Scope for Cause-Code-Initiated Call Establishment Retries

      ISDN Interface Example

      The following output shows that the ISDN interface is configured on the gateway and that the gateway is configured to reattempt disconnect calls received from the PSTN when the disconnect cause code is 18.

      Router# show running-config
      !
      interface Serial7/0:0
       no ip address
       isdn switch-type primary-ni
       isdn incoming-voice modem
       isdn T306 30000
       isdn rlm-group 0
       no isdn send-status-inquiry
       isdn negotiate-bchan resend-setup cause-code 18 ==> Cause-code 18 is configured.
       no cdp enable
      !
      end

      Cause Codes Example

      The following sample configuration shows that cause codes 34, 44, and 63 are set on serial slot 0 and port 23:

      Router# show running-config
      !
      interface serial0:23
       isdn negotiate-bchan resend-setup cause-codes 34 44 63
      end

      Additional References

      General ISDN References

      • "Overview of ISDN Voice Interfaces" --Describes relevant underlying technology; lists related documents, standards, MIBs, and RFCs; and describes how to obtain technical assistance
      • "Additional References" section --Lists additional ISDN references