Transcript “sos” URI parameter for marking emergency requests

“sos” URI parameter for marking
emergency requests
Milan Patel
5th SDO Emergency Services Workshop
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5th SDO Emergency Services Workshop 21-23 October 2008
Agenda
• 3GPP emergency registration
• Issues in 3GPP emergency services solution
• “sos” URI parameter
• Alternative solutions
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5th 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.
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5th SDO Emergency Services Workshop 21-23 October 2008
Issues in 3GPP release 7
1.
2.
3.
4.
4
Identification of emergency registration
Identification of emergency call from the UE (in
INVITE request)
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)
Identification of a call back
5th 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.
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5th SDO Emergency Services Workshop 21-23 October 2008
Back up
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5th SDO Emergency Services Workshop 21-23 October 2008
“sos” parameter in the emergency
INVITE
Le (e.g. E2)
P-CSCF adds “sos” URI
parameter in Contact if UE
does NOT detect emergency
session attempt. Service URN
is included in the RequestURI and To header
UE adds “sos” URI
parameter in Contact if UE
detects emergency
session attempt. Service
URN is included in the
Request-URI and To
header
LRF
2. Location &
Routing Function
Ml
PSAP URI added to
Route. “sos” URI
parameter
preserved in
Contact
from PSAP
to PSAP via IP
mutimedia
Network
Mm
UE
Gm
P-CSCF
Mw
E-CSCF
1. SIP INVITE
SIP REGISTER
Mw
Mi/Mg
3. SIP INVITE
or ISUP IAM
to PSAP
(via PSTN
via BGCF/
MGCF)
Registration
Outgoing Call
S-CSCF
Mm/Mw
from PSAP
Callback
Visited Network
2. SIP INVITE
Home Network
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5th SDO Emergency Services Workshop 21-23 October 2008
1. SIP INVITE
PSAP URI as tel URI added
to Request URI (replaces
service URN). BGCF URI
added to Route. “sos” URI
parameter preserved in
Contact