1. Interworking between SIP and QSIG for call transfer draft-rey-sipping-qsig2sip-transfer-00.txt Jean-Francois Rey jean-francois.rey@alcatel.fr Alcatel IETF59

2. Background QSIG is a signalling protocol between Private Integrated Services eXchanges (PINX) in enterprise networks. QSIG and SIP coexist in enterprise networks. Basic call qsig2sip is a SIPPING WG item draft-ietf-sipping-qsig2sip-04 Going beyond : presenting qsig2sip call transfer. It is related to other ecma-international works on qsig2sip. draft-rey-sipping-qsig2sip-transfer-00.txt2/6

3. Status draft-rey-sipping-qsig2sip-transfer-00.txt3/6 the document describes the mapping of QSIG and SIP at a gateway. One or two gateways may be involved. basic and attended transfers are in the scope. qsig2sip call transfer works with usual SIP extensions : REFER, replaces, referred-by. mechanisms at the gateway are proposed in order to minimize hair-pinning of signalling flows

4. Open issues (1/2) draft-rey-sipping-qsig2sip-transfer-00.txt4/6 How to indicate to a SIP UA that the identity of the remote party changed when a transfer has taken place in the PINX ? A B QSIG2SIP Gateway PINXSIP C B QSIG2SIP Gateway PINXSIP Dialog C A transfers B to C (in PINX)

5. Open issues (2/2) draft-rey-sipping-qsig2sip-transfer-00.txt5/6 How to transfer a call when the transfer target is still in alerting state ? The replaces header field does not match an early dialog at the UAS. INVITE 180 A C INVITE + replaces A-C dialog 481

6. Next step draft-rey-sipping-qsig2sip-transfer-00.txt6/6 Seeking guidance from the community on the call transfer mapping the open issues Solving these open issues could benefit to other use cases (third party call control, other types of gateways) Comments are welcome !