variable neighbourhood search based 0-1 Mip heuristics. Yugoslav Journal of Operations Research 25 (3): 343-360. 31 Huawei (2015). 5G Software Defined Protocol Runtime Test Report. Technical Report No. 1.0. Shenzhen, China: Huawei Technologies Co. Ltd. Flexible Function Split Over Ethernet Enabling RAN Slicing Ghizlane Mountaser and Toktam Mahmoodi Centre for Telecommunications Research, Department of Engineering, King's College London, UK 5G network aims at providing an infrastructure that is flexible to support a wide range of services and applications and satisfy their communication needs. Several factors, such as very high data rate, ultra-low latency, and high reliability, play a defining role in designing 5G infrastructure. Additionally, 5G network needs to be future proofing infrastructure, and hence, it needs to be scalable to support new features over the next several years. In addition, it needs to be flexible to adapt to a wide range of different service requirements and needs to be open. Above all, 5G network needs to be cost-effective for operators. In this context, Cloud-radio access network (RAN) and RAN slicing are the key technology components for 5G by enabling isolation [1], cloudification, and softwarization [2] of RAN functionalities. Cloud-RAN is envisaged as a promising solution for wireless systems to support the flexi- bility and high scalability of the network to keep up with traffic growth. Besides, RAN slicing has emerged as an efficient way to deploy diverse requirements for heterogeneous 5G ser- vices at the same time. RAN slicing aims at guaranteeing service experience requirements and maintaining performance. This could happen by slicing RAN and transport network resources. Flexible Functional Split Toward RAN Slicing 11.1.1 Full Centralization and CPRI Cloud-RAN, as one of the enablers of 5G, consists of two components, namely, remote radio head (RRH), also known as distributed unit (DU), that holds analog and radio frequency (RF) functions and baseband unit (BBU), also known as c