Redirection Number

Redirection Number subfield interworking includes:

• Nature of address indicator—The SBC inserts the following values into the IAM, based on the conditions described:

  • National, if there is no + in the number (encoded to 0000011).
  • International, if there is a + in the number (encoded to 0000100).
• Internal Network Number Indicator—The SBC always inserts the value routing to internal network number not allowed (1).
• Numbering Plan—The SBC always inserts the value ISDN (001.)
• Address Signal—The SBC inserts the URI of the last History-Info header containing a "cause" URI parameter.

Redirection Number Restriction

Redirection Number Restriction subfield interworking includes:

• APRI—This interworking is dependent on the value of either the SIP privacy header or the priv-value presented in the last History-info header with a cause parameter:
  • In the value is either 'History'. 'Session' or 'Header', map to presentation restricted (01).
  • If both values are absent or have values other than those above, map to presentation allowed (00).

Per standard, the priv-value component in the history-info header can only have values "history" or "none".

Call Diversion Information

Call Diversion Information subfield interworking includes:

• Notification subscription options—This interworking is dependent on the value of either the SIP privacy header or the priv-value presented in the History-info:
  • If there is a value in the Privacy header or priv-value component in the History-Info header, map to that value.
  • If the Privacy header received has the value "History", "Session" or "Header" or the SBC receives a priv-value of "History" in the headers component of both the diverted-to URI and the diverting URI(s), map to presentation not allowed (001).
  • If only the History-Info header with a priv-value of history, map to presentation allowed without redirection number (011).
  • In all other cases, map to presentation allowed with redirection number (010).
• Redirecting Reason—The SBC maps this value based on the cause parameter of the last HI entry that contains a cause parameter.
  • Cause Parameter 404—Maps to the value Unknown (0000)
  • Cause Parameter 302—Maps to the value Unconditional (0011)
  • Cause Parameter 486—Maps to the value User Busy (0001)
  • Cause Parameter 408—Maps to the value No Reply (0010)
  • Cause Parameter 480—Maps to the value Deflection immediate response (0101)
  • Cause Parameter 503—Maps to the value Mobile Subscriber not reachable (0110)
  • Cause Parameter 487—Maps to the value Deflection during alerting (0100)

Additional context information includes:

• The diverted-to URI corresponds to the hi-targeted-to-uri of the last hi-entry containing a "cause" URI parameter.
• The diverting URI corresponds to the hi-targeted-to-uri of the hi-entry containing a hi-index value that match the "mp" header field parameter value of the diverted-to URI. If the diverted-to URI does not contain the "mp" header field parameter, the diverting URI corresponds to the hi-targeted-to-uri of the hi-entry before the last hi-entry containing a "cause" URI parameter.
• If there is no diverting URI (for example, an HI entry with hi-index matching "mp" param of last hi-entry with "cause" param is present) the hi-entry to use is the entry just before the last hi-entry with a cause parameter.
• If there is only a diverted-to URI and no other URI, the SBC only refer to the diverted-to URI while populating the "Notification subscription options" parameter.

Generic Notification Indicator

In addition, the SBC sets the Generic Notification Indicator in the ACM or CPG to Call is Diverting (11111011).