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Work item:
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Q.Sig_Req_ETS_IMS_roaming
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Subject/title:
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Signalling requirements for emergency telecommunication service in IMS roaming environment
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Status:
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[Carried to next study period]
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Approval process:
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AAP
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Type of work item:
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Recommendation
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Version:
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New
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Equivalent number:
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-
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Timing:
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-
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Liaison:
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ITU-T SG2, 3GPP SA6
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Supporting members:
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China Telecom; China Mobile; China Unicom; IAFI
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Summary:
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After a successful LTE (Long Term Evolution) introduction into mobile networks for broadband data, VoLTE /ViLTE and other IMS services are progressively opened. The interconnection and roaming among different IMS domains are essential capabilities for providing the P2P IMS service across the world.
There are two IMS roaming architecture alternatives described in GSMA IR.65, namely IMS Roaming Architecture using LBO (Local Breakout) and IMS Roaming Architecture using S8HR (S8 Home routed). There is IMS-level roaming interfaces in LBO architecture and no IMS-level roaming interfaces in S8HR architecture. Since the emergency telecommunication services are provided by the visiting network, the implementations of emergency telecommunication service are quite different in these two architectures.
Additional capabilities are required to support the IMS emergency sessions for roaming users in deployments of S8HR architecture without IMS-level roaming interfaces. 3GPP TS 23.167 addresses the IP Multimedia Subsystem?IMS?emergency sessions and illustrates a diagram in support of the IMS emergency sessions for roaming users in S8HR architecture. However, there are still some unresolved issues within the diagram, such as how to transfer the CallBackPar parameter in an initial SIP INVITE.
In addition, there is a lack of a comprehensive specification of emergency telecommunication service in IMS roaming environment, which could particularly address the architecture model, functional description, signalling requirements and procedure of ETS for IMS roaming users.
The goal of this document is to present the signalling architecture, interfaces, functional description, signalling requirements, signalling procedures and security consideration of Emergency Telecommunication Service (ETS) in IMS roaming architecture over LTE. As more and more operators have launched the VoLTE service, it's a big challenge for the industry to provide ETS in IMS roaming environment. The standardization for ETS in IMS roaming environment is in urgent demand.
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Comment:
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-
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Reference(s):
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Historic references:
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Contact(s):
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First registration in the WP:
2020-11-11 09:31:55
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Last update:
2021-12-22 13:54:18
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