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This object creates a Crankback Profile containing a table of call release codes used by the SBC Core to attempt to reroute (or "crankback") a call when a matching code is returned by Egress Signaling. Release codes may be added or removed from this table. Removing a release code from the table causes the SBC software to return that release code to Ingress Signaling rather than attempt to reroute the call.

You can configure up to 20 Crankback Profiles (including default profile). As profiles are created, they are assigned indexes 2, 3, 4, and so on by the SBC (index 1 is reserved for default profile). Index assignments are viewable using the show command.

Use the crankback index number to assign a particular Crankback Profile to a particular SIP, or H.323 trunk group for ingress signaling.

This object influences rerouting policy for SIP 3xx Redirection processing if the IP Profile is configured to use the Crankback Profile. For example, when a SIP 3xx Redirect is initiated and a SIP INVITE message is issued, if a disconnect release code is returned in the SIP response, the Crankback Profile is examined for a matching code. If a matching code is found and at least one more SIP redirect destination is present, a SIP INVITE is issued to that destination.

This scenario is repeated up to ten times, after which additional SIP redirect destinations are disregarded as if not present. However, only four Contact headers in a redirect are accepted and processed. If more than four Contact headers are sent, they are ignored.

If a matching code is found but no additional SIP redirect destination is present, the SIP redirect is terminated with that code. If no matching code is found in the Crankback Profile, then the SIP redirect is terminated with that (unmatched) code. 

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 ATTEMPT record in accounting file after each crankback.

  • disabled (default)
  • enabled

lateCrankback

N/A

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

  • disabled (default)
  • enabled

reason

1-255

Call termination reason code value, plus associated location
(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 use Location table values for this reason code while cranking back on 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

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