Diversion to History-Info Header Interworking

When configured for this interworking, the SBC takes the following steps for all Diversion headers in the incoming initial INVITE:

1. Create a new History-Info header.
2. Add the index header parameter.
3. Set the value for the first header to 1. Append .1 to the value of the last_index_value for the subsequent headers.
4. If the Diversion header contains a privacy parameter, add the Privacy header parameter to the History-Info header using the following conversion table.

   Diversion Privacy	History-Info Privacy
   full	history
   name	history
   uri	history
   off	none

5. If the previous Diversion header contains a reason parameter, add the cause header parameter to the History-Info header using the following conversion table. The SBC does not add a cause parameter to the first History-info entry.

   Diversion Reason	History-Info Cause
   unknown	404 (default value)
   unconditional	302
   user-busy	486
   no-answer	408
   deflection	480
   unavailable	404
   time-of-day	404
   do-not-disturb	404
   follow-me	404
   out-of-service	404
   away	404

6. If the presented reason parameter is not in the table above, set the parameter to the default value of 404.
7. Remove the diversion header from the outgoing INVITE.

The diagram below provides an example flow and the header text used for this example.