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Use the crankbackProfile object to configure 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.

Command Syntax

% set profiles callRouting crankbackProfile <profile_name> 
	attemptRecordGeneration <disabled | enabled> 
	lateCrankback <disabled | enabled> 
	reason <reason code, 1-255> 
		location <location type> 
		useLocationValue <disabled | enabled>

Command Parameters

The crankback profile parameters are as shown below:

Command Parameters

Parameter

Length/Range

Description

crankbackProfile

1-23

The name of the crankback profile.

attemptRecordGeneration

N/A

Enable this flag to log an ATTEMPT record in accounting file after each crankback.

  • disabled (default)
  • enabled

lateCrankback

N/A

Enable this flag to allow crankback after an ALERTING, PROCEEDING, or equivalent backwards call message is received from the egress network.

  • disabled (default)
  • enabled

reason

1-255

Call termination reason code value to include in the profile, and optionally associate a location value with the reason code.
(Refer to Call Termination Reason Codes page for call termination reason codes list).

  • <reason_code>
  • location
    • gwLinkFailure – Allows the GW-GW signaling link (TCP connection) failure to initiate call crankback. To crankback for GW-GW link failures only, set useLocationValue to enabled, reason code to 3, and Location value to gwLinkFailure.
    • internationalNet – International network.
    • natReserved6 Reserved
    • natReserved12 Reserved
    • netBeyondInterPoint Network beyond interworking point (BI).
    • privateLocal Private network serving the local user (LPN).
    • privateRemote Private network serving the remote user (RPN).
    • publicLocal Public network serving the local user (LN).
    • publicRemote Public network serving the remote user (RLN).
    • transitNet Transit network (TN)
    • user
  • useLocationValue – Enable flag to require the location table values for this reason code before cranking back to the next route.
    • disabled (default)
    • enabled

Command Example

% set profiles callRouting crankbackProfile CB_CUSTOM attemptRecordGeneration enabled lateCrankback enabled reason 10 location publicLocal 
% set profiles callRouting crankbackProfile CB_CUSTOM reason 11 location internationalNet 
% commit

% show profiles callRouting crankbackProfile CB_CUSTOM
	lateCrankback enabled; 
	attemptRecordGeneration enabled; 
	reason 10 {
		location publicLocal; 
	} 
	reason 11 { 
		location internationalNet; 
	} 
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. The CPC cause is then looked up 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