Implementation of OpenAPI Wireshark Dissectors to Validate SBI Messages of 5G Core Networks
Lukas Schauer, Thorsten Horstmann, Steffen Druesedow, Michael Rademacher
TL;DR
The paper tackles protocol validity for 5G Core SBI by developing an OpenAPI-based validator implemented as a Wireshark Lua post-dissector. It leverages OpenAPI YAMLs and a Python generator to map API paths to schemas, enabling offline trace validation. Evaluation across three open-source 5GC implementations (Open5GS, free5GC, OpenAirInterface) with UERANSIM reveals multiple specification deviations, underscoring interoperability risks. The work provides an open-source tool that helps developers and operators enforce specification conformance and improve network reliability, with future work to extend validation to longer procedures and synchronized operation sequences.
Abstract
This paper introduces a novel Wireshark dissector designed to facilitate the analysis of Service-Based Interface (SBI) communication in 5G Core Networks. Our approach involves parsing the OpenAPI schemes provided by the 5G specification to automatically generate the dissector code. Our tool enables the validation of 5G Core Network traces to ensure compliance with the specifications. Through testing against three open-source 5G Core Network projects, we identified several issues where messages deviate from specification standards, highlighting the significance of our implementation in ensuring protocol conformity and network reliability.