etworks and offers great flexibility. However, packet-based FH imposes many challenges such as high latency and high jitter. Nevertheless, it can be used in functional split where the latency and jitter requirements are relaxed. For example, the feasibility of splitting between MAC and PHY was demonstrated in [8]. In standard deployments of packet-based FH, enhanced CPRI [9] and IEEE 1914 Radio over Ethernet provide a framework for transport of radio data over Ethernet. 11.2.2 Multipath Packet-based Fronthaul for Enhancing Reliability In addition to low latency and excessive data rate, reliability is also an important metric in 5G [10], [11] as many use cases will rely on reliability. Under the Cloud-RAN architec- ture, FH needs to provide comparative reliability to enable adoption of Cloud-RAN. The 11 Flexible Function Split Over Ethernet Enabling RAN Slicing most well-used methods to improve reliability are retransmission, multipath with packet duplication (MPD), and multipath with coding (MPC). Retransmission is a straightforward way to achieve reliability. However, retransmission can have significant impact on increas- ing the latency, making it a non-viable solution on the FH where delays cannot be afforded. By contrast, path diversity with duplication offers better latency in the expense of signifi- cant transmission overhead by duplicating packets over multiple interfaces increasing FH network congestion. Two important considerations in such approaches are latency and FH overhead. An alternative solution that provides trade-off between latency and FH overhead is channel coding, which can add redundancy to achieve the desired reliability and splits the total amount of information to transmit across different paths. For example, fountain coding is used in a number of different domains; such domains include broadcasting sys- tem [12], [13], content download [14], and over air interface [15], and has been proved to enhance reliability. 11.2.3 Slicing Within Multipath Fronthaul FH resource sharing can be catego