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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.
The Crankback Profile Parameters are as shown below:
The name of the Crankback Profile.
Enable this flag to log ATTEMPT record in accounting file after each crankback.
Enable flag to allow crankback after an ALERTING, PROCEEDING, or equivalent backwards call message is received from egress network.
Call termination reason code value, plus associated location
Notes on Using Crankback for DNS