1. 1 5 th SDO Emergency Services Workshop 21-23 October 2008 “sos” URI parameter for marking emergency requests Milan Patel 5 th SDO Emergency Services Workshop

2. 2 5 th SDO Emergency Services Workshop 21-23 October 2008 Agenda 3GPP emergency registration Issues in 3GPP emergency services solution “sos” URI parameter Alternative solutions

3. 3 5 th SDO Emergency Services Workshop 21-23 October 2008 Emergency registration 3GPP release 7 requirement UE registers to attach to IMS via visited P-CSCF UE performs emergency registration if: UE is not registered or is registered in IMS but is roaming Has credentials to register in IMS and is emergency aware Removal of Emergency public user identity from release 7 removes indication of emergency registration – need to mark emergency registration and registered contact address for special handling of services and call back.

4. 4 5 th SDO Emergency Services Workshop 21-23 October 2008 Issues in 3GPP release 7 1.Identification of emergency registration 2.Identification of emergency call from the UE (in INVITE request) 3.Identification of emergency call towards the UE (in response to INVITE request, in the case where the UE was not aware that it sets up an emergency call) 4.Identification of a call back

5. 5 5 th SDO Emergency Services Workshop 21-23 October 2008 “sos” URI parameter The proposed solution intends to solve all 4 problems NOT a replacement for urn:service:sos Current proposal appends “sos” URI parameter to the contact address in the Contact header of SIP requests and responses This URI parameter is mandated only for the registration case In the event that standardization of the “sos” URI parameter is unsuccessful, 3GPP are considering the use of IMS Communication Service Identifier to mark emergency registration. This does not solve all four issues with the 3GPP solution.

6. 6 5 th SDO Emergency Services Workshop 21-23 October 2008 Back up

7. 7 5 th SDO Emergency Services Workshop 21-23 October 2008 “sos” parameter in the emergency INVITE UE adds “sos” URI parameter in Contact if UE detects emergency session attempt. Service URN is included in the Request-URI and To header P-CSCF adds “sos” URI parameter in Contact if UE does NOT detect emergency session attempt. Service URN is included in the Request- URI and To header PSAP URI as tel URI added to Request URI (replaces service URN). BGCF URI added to Route. “sos” URI parameter preserved in Contact PSAP URI added to Route. “sos” URI parameter preserved in Contact