Evolution of NGN Control Plane for Future Telecommunications Networks

The future telecommunications networks (IMT-2030 and beyond) are anticipated to capacitate a wide range of use cases with differing requirements, such as high-speed and latency-tolerant communication, or hyper-reliable and low-latency communication. It is therefore imperative that the future network architecture is scalable, and flexible to support the wide-ranging needs presented by these emerging use cases. To this end, the International Telecommunication Union (ITU) is engaged in evolving the architecture for future telecommunications networks through its Study Group 13 (SG13), “Future networks”. In ITU terminology, an abstract architecture for an existing packet-based telecommunications network, such as, the 4th Generation (4G) network or fixed broadband network is known as Next Generation Network (NGN) and its future evolution beyond IMT-2020 has been christened as “NGNe”. One of the key components of the NGN architecture is the “transport stratum”. The transport stratum comprises user data transfer functions (known as user plane) along with functions to control them (known as control plane). In addition to controlling the user plane, the control plane is also responsible for signalling exchange with the end-user devices. Both these functionalities are tightly coupled within the control plane of the NGN transport stratum. However, we believe these functionalities are distinct and should be handled separately. In this article, we propose to move the signalling handling functionality out of the NGN control plane and treat it as payload (data), handled via service functions outside the control plane. Separating these two groups of functionalities leads to a scalable, flexible, and modular control plane for future telecommunications networks (NGNe). Information flows for procedures and network services like registration, authentication, and mobility are presented to validate the advantages of the proposed architecture. We also elucidate an ongoing standardization activity under ITU related to this work.