SMF and PGW IP Mapping for EPC-5GC Mobility Interworking
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Solution Overview
Problem
Mobility between EPC and 5GC, and/or ePDG and LTE may fail in existing solutions due to the lack of compatibility in IP address handling, leading to issues in network interface interactions.
Innovation Solution
Introduce the use of PGW IP address as a query parameter in SBI interfaces and convert it into an octet string for SBI interfaces to support EPC and 5GC interworking without impacting existing EPC network interfaces, or add specific logic in SMF and HSS to handle PGW IP address conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PGW IP address is used as query parameter in SBI interfaces, then mobility between EPC and 5GC is improved, but interface complexity increases
Solution Approach 1:
The patent introduces PGW IP address as an intermediary query parameter that mediates between EPC and 5GC systems. This intermediary element enables reliable mobility by providing a common identifier that both systems can use, while the complexity is managed through the standardized SBI interface framework.
Solution Approach 2:
The PGW IP address serves multiple functions: it acts as a query parameter for SMF discovery, identifies the PGW-C+SMF combination, and enables mobility between different access types (3GPP and non-3GPP). This multi-functionality improves reliability without proportionally increasing complexity.
2Adaptability or versatility
If PGW IP address conversion to octet string is implemented, then compatibility with existing FQDN fields is improved, but data processing complexity increases
Solution Approach 1:
The patent applies parameter changes by converting the PGW IP address from its native format to an octet string representation. This parameter transformation enables compatibility with existing FQDN fields in the SBI interface, allowing the system to reuse existing data structures without fundamental redesign.
Solution Approach 2:
The conversion process creates a copied representation of the PGW IP address in octet string format. This copy can be processed through existing FQDN handling mechanisms, maintaining compatibility while enabling new functionality. The copying approach isolates the complexity to a specific transformation step rather than requiring system-wide changes.
3Reliability
If SMF discovery uses PGW IP address, then service discovery reliability is improved, but query processing complexity increases
Solution Approach 1:
The PGW IP address serves as an intermediary query parameter that mediates between the AMF's service discovery needs and the SMF's identification requirements. This intermediary element improves discovery reliability by providing a stable, unique identifier that can be reliably queried and matched across different network functions.
Data Source
AI summary
Methods and apparatuses for mobility between different communication systems are disclosed. According to an embodiment, a session management function (SMF) sends, to a service provider, a request for registering information related to the SMF to the service provider. The information related to the SMF comprises information indicating or derived from an Internet protocol (IP) address of a packet data network (PDN) gateway (PGW) control plane (PGW-C) that is combined together with the SMF. The SMF receives, from the service provider, a response to the request.