Mapping%20and%20interworking%20of%20Diversion%20information%20between%20Diversion%20and%20History-Info%20Headers%20in%20the%20SIP%20draft-mohali-bliss-diversion-history-info-00

1
Mapping and interworking of Diversion information
between Diversion and History-Info Headers in
the SIP draft-mohali-bliss-diversion-history-info
-00

• M. Mohali (France Telecom), S. Norreys (British
  Telecom),
• J. Van Geel (Belgacom), M. Dolly (ATT),
• F. Silva (Portugal Telecom), G. Sciortino, C.
  Amenta (Italtel)

2
Context about Call-Forwarding

• Need to transport call forwarding information to
  a UA (regular user, voicemail, call-center, or
  other downstream element)
• 2 solutions
• Diversion header
• Proprietary solution documented in
  draft-levy-sip-diversion
• Widely implemented and deployed
• History-Info header
• IETF standard solution (RFC4244), also adopted by
  other standardization bodies (e.g. 3GPP and
  TISPAN)
• Not yet widely implemented nor deployed
• In order to migrate towards the History-Info
  solution, there is a need to support interworking
  between History-Info and Diversion for backward
  compatibility.

3
Interworking Problem

• The two headers differ in scope, syntax and
  semantics
• History-Info
• ltsipproxyP1gt index1,
• ltsipuserBgt index1.1
• ltsipuserCgt cause302 index1.1.1
• ltsipuserDgt cause408 index1.1.1.1
• Diversion
• C reason no-answer counter1,
• B reason unconditional counter1
• Rules should be defined to ensure that
  manufacturers apply the same interworking
  procedures.
• Lack of clear mapping between both headers
  results in significant interoperability issues
  and therefore delay widespread implementation of
  the History-Info header.

4
Proposal

• Map call forwarding information contained in a
  Diversion header into a History-Info header, and
  vice versa.
• Make some recommendations
• For example "When the Diversion header is mapped
  into a History-Info header, the Diversion header
  MUST be removed".

5
Next steps

• Is there some interest for this problem ?
• If yes, where and how the work should progress?
• In the draft add mapping between Diversion
  header and Voicemail and IVR URI (RFC4458).