1. Mapping and interworking of Diversion information between Diversion and History-Info Headers in the SIP draft-mohali-bliss-diversion-history-info-00 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-diversiondraft-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)RFC4244 -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: ; index=1, ; index=1.1 ; cause=302; index=1.1.1 ; cause=408; index=1.1.1.1 Diversion: C; reason= no-answer; counter=1, B; reason= unconditional; counter=1 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).