SIP Transport Protocol Selection for IMS Signaling Reliability
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Solution Overview
Problem
IMS signaling is often lost during EPS fallback in 5G networks due to the lack of a direct connection between 5GC AMF and EPC MME, leading to delays and inefficiencies in IMS MMTEL session setup.
Innovation Solution
Establishing a TCP connection between the UE and P-CSCF for IMS signaling, allowing for guaranteed delivery of SIP messages and converting between TCP and UDP transport protocols as needed to optimize transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCP connection is used between UE and P-CSCF for guaranteed delivery, then reliability of SIP message delivery is improved, but transmission speed and efficiency deteriorate
Solution Approach 1:
The patent applies different transport protocols (TCP vs UDP) to different segments of the IMS signaling path. TCP is used between UE and P-CSCF for reliable delivery, while UDP may be used between P-CSCF and S-CSCF where speed is more critical. This local differentiation of protocol quality resolves the contradiction by optimizing each segment's transport protocol according to its specific requirements.
2Reliability
If TCP protocol is used for all IMS signaling, then message delivery reliability is improved, but network overhead and processing complexity increase
Solution Approach 1:
The patent implements local quality by selectively applying TCP only where reliability is critical (UE to P-CSCF interface) while allowing UDP in other segments (P-CSCF to S-CSCF). This reduces overall protocol processing complexity and network overhead while maintaining reliability where needed, resolving the contradiction between reliability and complexity.
3Productivity
If UDP is used for faster transmission, then transmission efficiency is improved, but message delivery reliability deteriorates
Solution Approach 1:
The patent applies UDP in segments where transmission efficiency is prioritized (such as between P-CSCF and S-CSCF) while using TCP in segments where reliability is critical (UE to P-CSCF). This local differentiation allows the system to achieve high transmission efficiency where possible while maintaining reliability where necessary, resolving the contradiction between productivity and reliability.
Data Source
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AI summary
Apparatuses, methods, and systems are disclosed for selecting a transport layer protocol for SIP messages. One apparatus 600 includes a processor 605 and a transceiver 625 that receives 805 a SIP message from a remote unit, the SIP message comprising a first request to initiate a session for an IMS MMTEL. The processor 605 determines 810 that the SIP message is communicated using TCP as a transport layer protocol and forwards 815 the first request to a network entity, wherein the first request is sent using UDP as the transport layer protocol.