5G is under development and coming soon(ish) to a network near you. To meet the needs of the range of services envisioned for 5G, with diverse performance requirements, across a wide variety of industries, the networking industry needs to develop a new 5G system architecture (5GS), including 5G New Radio (NR) access and a new 5G core network (5GC).
Much has been written about the 5G RAN and the design of the radio interface, but from a services perspective, the 5G core is also important. The mobile core network is responsible for functions such as session management, mobility, authentication, and security. As such, it is critical to delivering services in a 5G network.
In Technical Specification (TS) 23.501 -- known as System Architecture for the 5G System -- the 3GPP is currently standardizing what is known as the Service-Based Architecture (SBA) for 5G Core. It uses service-based interfaces between control-plane functions, while user-plane functions connect over point-to-point links. This is shown in the figure below. The service-based interfaces will use HTTP 2.0 over TCP in the initial release, with QUIC transport being considered for later releases.
In a new Heavy Reading white paper -- Service-Based Architecture for 5G Core Networks -- I discuss various aspects of this new core network design. One of the interesting things about the new architecture is how it maps to cloud infrastructure. There are many aspects to this, but the white paper highlights:
- How the idea of "network function services" (3GPP terminology) aligns with the micro-services based view of network service composition
- How operators may take advantage of decoupled control- and user-plane to scale performance
- How the design might enable operators to deploy 5GC functions at edge locations, such as central offices, stadiums or enterprise campuses
The first 5G core standards are scheduled to be included in 3GPP Release 15, which "freezes" in June next year and will be formally approved three months later. This will be a critical release for the industry that will set the development path of the 5G system architecture for years to come.