Protocol Details from 3GPP TS 24.229 2006-09-29 Protocol Details from 3GPP TS 24.229 SDO Emergency Services Coordination Workshop (ESW06) Columbia University, New York October 5-6, 2006 Atle Monrad, Ericsson Mobile Platform (atle.monrad@ericsson.com) Ericsson AB 2006

Stage-3 specification ’philosophy’ 2006-09-29 Stage-3 specification ’philosophy’ 3GPP TS 24.229 specifies the involved IMS entities Reference relevant IETF-RFCs Profile RFCs if only parts are supported Specify additions and limitations Work is ongoing and is planned to be completed by mid-2007 Ericsson AB 2006

Involved entities UE - User Equipment Proxy-CSCF Serving-CSCF 2006-09-29 Involved entities UE - User Equipment Proxy-CSCF Serving-CSCF Emergency-CSCF Ericsson AB 2006

UE – User equipment Performs registration to the home IMS network 2006-09-29 UE – User equipment Performs registration to the home IMS network The emergency call is handled in the visiting network, thus a dedicated emergency registration is needed when the terminal can move out of the home network Decides whether CS or IMS domain shall be used for initial emergency call attempts Can perform emergency call without SIM/UICC Open issues: - when is a dedicated emergency registration needed? - How to indicate that location is not available? - How to transfer the equipment identifier? Ericsson AB 2006

Proxy-CSCF Is the initial point for communication with terminals 2006-09-29 Proxy-CSCF Is the initial point for communication with terminals Is access-agnostic Open issues: - when is a dedicated emergency registration needed? - How can the P-CSCF discover whether the terminal is in the home network? Ericsson AB 2006

2006-09-29 Serving-CSCF Is the central point in the home network handling the subscriber Involved for emergency calls due to differences between normal registrations and emergency registrations Open issues: - No major Ericsson AB 2006

Emergency-CSCF Is the interface towards the PSAP 2006-09-29 Emergency-CSCF Is the interface towards the PSAP Open issues: - How to mark an emergency session after the PSAP address has been resolved between the E-CSCF - PSAP and the E-CSCF - MGCF? - The use of the Resource-Priority header? - MGCF interworking; any regulatory requirements? Ericsson AB 2006

Other issues Where shall the requirements on the PSAP be specified? Call-back from the PSAP is currently not included. The location is in current deployment often based on A-number and cell-identity. Should LOST also consider these as ’valid locations’, as existing databases in many cases are based on this?

2006-09-29 Ericsson AB 2006