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 Use the Crankback Profile window to work with crankback profiles.

A crankback profile consists of a list of call release codes that the SBC uses to determine whether to reroute (or "crankback") a call if the call does not connect successfully to the initial destination. If egress signaling returns a release code that is in the reason code list in the crankback profile, the SBC attempts to crankback the call. If a release code is not in the list, the SBC returns the release code to ingress signaling rather than attempting to reroute the call. 

You can configure which release codes trigger rerouting by adding or removing release codes from a crankback profile. You also have the option to associate a location value with a specific reason code. When a location is configured and enabled, the specified location value must be included along with the reason code in the egress disconnect signaling to trigger crankback. Including a location with a reason code is optional.

The SBC provides a default crankback profile (named "default"), the contents of which can be edited. Or, you can create your own crankback profiles. The SBC supports a total of 20 crankback profiles in the system.

For flexibility, crankback profiles can be assigned at three levels: trunk group, zone, and global. By default, the "default" crankback profile is assigned at the SBC global level, while the trunk group and zone level crankback profile settings are initially empty (" "). Thus in the SBC default configuration, trunk groups and zones inherit the default crankback profile from the global level. However, if you configure a profile at the trunk group or zone level, the user-specified profile assigned at the most specific level takes precedence.

To View Crankback Profiles

On the SBC main screen, go to Configuration > Profile Management > Category: Call Routing Profiles > Crankback Profile or
All > Profiles > Call Routing > Crankback Profile 

To Create a Crankback Profile

To create a new crankback profile:

  1. Click New Crankback Profile. 

  2. Use the following table to name and configure the general options for the profile.
    Crankback Profile Parameters:

    Parameter

    Description

    Name

    Enter a name of up to 23 characters for the crankback profile.

    Late Crankback

    Specifies whether to allow crankback after an ALERTING, PROCEEDING, or equivalent message (backwards call message) is received from the egress network:
    • Enabled – allow crankback after a backwards call message is received.
    • Disabled (default) – do not allow crankback after a backwards call message is received.

    Attempt Record
    Generation

    Specifies whether the SBC 5000 series should generate an ATTEMPT accounting record whenever a call is rerouted (cranked back):
    • Enabled – generate an ATTEMPT record when a call is rerouted.
    • Disabled (default) – do not generate an ATTEMPT record when a call is rerouted.

  3. Click Save. After configuring the general options, edit the list of reason codes and optionally add location parameters using the Reason and Location windows.

To Edit a Crankback Profile

To edit an existing crankback profile:

  1. Click the radio button next to the name of the crankback profile you want to edit. 

  2. Make the required changes and click Save.

To Delete a Crankback Profile

To delete an existing crankback profile:

  1. Click the radio button next to the name of the crankback profile you want to delete. 
  2. Click the delete icon (X) at the end of the row.
  3. Confirm the deletion when prompted.


Notes on Using Crankback for DNS
  • dnsCrankback needs to be enabled on the egress sipTrunkGroup.
  • The crankbackProfile assigned to the egress sipTrunkGroup is used for DNS crankback.
  • The  SBC maps the received SIP response from the egress call leg using the sipToCpcCauseMapProfile from the egress sipTrunkGroup. It then looks up the CPC cause code in the egress sipTrunkGroup's crankbackProfile.
    • If a match is found, the SBC attempts a new target.
    • If a match is not found, SBC skips the DNS crankback and proceeds with the normal crankback at CC level using the ingress sipTrunkGroup's crankback profile.