Roaming Hub SEPP Architecture for 5G PLMN Interconnect

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Solution Overview

Problem

The existing 3GPP specifications do not define how a Roaming Hub (RH) SEPP can establish interconnectivity between visiting PLMNs and home PLMNs that have no prior business relationship, complicating roaming agreements and communication between SEPPs.

Innovation Solution

A Roaming Hub architecture is introduced, where the RH SEPP is configured to establish interconnectivity between any visiting PLMN and home PLMN with a roaming agreement through a hosted SEPP system, including a producer and consumer SEPP, and utilizes an RH SCP and rhSBI bus for secure communication and routing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a Roaming Hub SEPP is introduced to simplify roaming connectivity between operators, then the complexity of bilateral roaming agreements is reduced, but the configuration and establishment of interconnectivity between SEPPs becomes undefined and complex

Engineering Contradiction:
Improveroaming agreement complexityVSAvoidSEPP interconnectivity establishment
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent introduces an intermediary configuration mechanism where the Roaming Hub SEPP acts as a mediator between visiting and home PLMN SEPPs. The hub SEPP maintains configuration data about multiple home PLMN SEPPs and automatically routes signaling traffic through appropriate intermediaries, eliminating the need for direct bilateral configurations between all operator pairs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The Roaming Hub SEPP is designed with multi-functionality to handle multiple roles simultaneously: it serves as a security edge protection proxy, a routing intermediary, and a configuration repository. This universal design allows a single entity to manage interconnectivity for multiple PLMN pairs without requiring separate configuration mechanisms for each relationship.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If SEPPs establish direct interconnectivity between all roaming partners, then communication security is maintained, but the number of required SEPP connections increases significantly

Engineering Contradiction:
Improvecommunication securityVSAvoidnumber of SEPP connections
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the mesh-like direct connection architecture into a hub-and-spoke topology. Instead of requiring every SEPP to connect directly to every other SEPP, the architecture divides connections into two segments: (1) visiting PLMN SEPPs connect to the Roaming Hub SEPP, and (2) the Hub SEPP connects to home PLMN SEPPs. This segmentation reduces the total number of connections while maintaining security through the Hub's intermediary security functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The Roaming Hub SEPP serves as a security intermediary that mediates all communications between visiting and home PLMN SEPPs. It performs security edge protection functions, message filtering, and policing on inter-PLMN control plane interfaces while maintaining topology hiding. This intermediary approach preserves communication security by ensuring all traffic passes through validated security checks at the Hub, even though direct connections are reduced.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the Roaming Hub SEPP is made visible as a network entity with security requirements, then security is enhanced, but the configuration and management of PLMN-IDs becomes more complex

Engineering Contradiction:
ImprovesecurityVSAvoidPLMN-ID negotiation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary configuration where the Roaming Hub SEPP pre-stores configuration data about multiple home PLMN SEPPs, including their PLMN-IDs and routing information. This preliminary action allows the Hub to automatically match and negotiate PLMN-IDs during runtime without requiring complex real-time negotiations, as the validation rules and acceptable PLMN-ID ranges are pre-established in the configuration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms where the Roaming Hub SEPP validates received PLMN-IDs against its pre-configured lists of authorized home PLMN SEPPs. If a PLMN-ID does not match the configuration, the Hub provides feedback by rejecting the connection attempt and can log the discrepancy. This feedback loop ensures security validation while simplifying the negotiation process, as the Hub autonomously verifies PLMN-IDs without requiring complex multi-party negotiations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4240103B1Roaming hub 5g interconnect for public line mobile networks
Publication Date: 2025.11.12 MAVENIR NETWORKS INC
  • EP4240103B1 patent drawingFigure 1
  • EP4240103B1 patent drawingFigure 2A
  • EP4240103B1 patent drawingFigure 2B

AI summary

A method and an architecture for the Roaming Hub that can be configured to establish interconnectivity between any visiting Public Line Mobile Network (PLMN) and home PLMN as long as the visiting PLMN and the Home PLMN has a roaming agreement with the Roaming Hub.