Inter-Slice Mobility Management in 5G: Motivations, Standard Principles, Challenges and Research Directions

Mobility management in a sliced 5G network introduces new and complex challenges. In a network-sliced environment, user mobility has to be managed not only among different base stations or access technologies, but also among different slices. This motivates the need for new mobility management solutions, which, by convention are required to be standards-compliant. This article, presented as a tutorial, focuses on the problem of inter-slice mobility from the perspective of 3GPP standards for 5G. A detailed overview of the relevant 3GPP standard principles is provided. Accordingly, the key technical gaps, challenges and the corresponding research directions are identified towards achieving seamless inter-slice mobility within the current 3GPP network slicing framework

Inter-Slice Mobility Management in 5G: Motivations, Standard Principles, Challenges and Research Directions

Mobility management in a sliced 5G network introduces new and complex challenges. In a network-sliced environment, user mobility has to be managed among not only different base stations or access technologies but also different slices. Managing user mobility among slices, or inter-slice mobility, motivates the need for new solutions. This article, presented as a tutorial, focuses on the problem of inter-slice mobility from the perspective of 3GPP standards for 5G. It provides a detailed overview of the relevant 3GPP standard principles. Accordingly, key technical gaps, challenges, and corresponding research directions are identified toward achieving seamless inter-slice mobility within the current 3GPP network slicing framework

On session continuation among slices for inter-slice mobility support in 3GPP service-based architecture

The 3GPP has provided its first standard specifications for network slicing in the recent Release 15. The fundamental principles are specified which constitute the standard network slicing framework. These specifications, however, lack the session continuation mechanisms among slices, which is a fundamental requirement to achieve inter-slice mobility. In this paper, we propose three solutions which enable session continuation among slices in the current 3GPP network slicing framework. These solutions are based on existing, well-established standard mechanisms. The first solution is based on the Return Routability/Binding Update (RR/BU) procedure of the popular Internet standard, Mobile IPv6 (MIPv6). The second solution is based on the 3GPP standard GPRS Tunnelling Protocol User Plane (GTPv1-U), which establishes a GTP tunnel between previous and new slice for session continuation. The third solution is a hybrid solution of both MIPv6-RR/BU and GTPv1-U protocols. We compare the performance of all these solutions through analytical modelling. Results show that the GTPv1-U based and the hybrid MIPv6/GTPv1-U solutions promise lower service disruption latency, however, incur higher resource utilization overhead compared to MIPv6-RR/BU and 3GPP standard PDU Session Establishment process