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

2. Stage-3 specification ’philosophy’
Stage-3 specification ’philosophy’
3GPP TS 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

3. Involved entities UE - User Equipment Proxy-CSCF Serving-CSCF
Involved entities
UE - User Equipment
Proxy-CSCF
Serving-CSCF
Emergency-CSCF
Ericsson AB 2006

4. UE – User equipment Performs registration to the home IMS network
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

5. Proxy-CSCF Is the initial point for communication with terminals
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

6.
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

7. Emergency-CSCF Is the interface towards the PSAP
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

8. 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?

9.
Ericsson AB 2006