support for non-native radio data where the transport structure is simply a container for the data (see Fig. 1.35). IEEE 1914.3 has further IEEE 1914.3: Standard for radio-over-Ethernet encapsulations and mappings (http://sites.ieee.org/sagroups- 1914/p1914-3/). 82 Chapter 1 Logical connection for timing packets Logical connection for control packets Logical connection for data packets RoE node Pass-thru Termination Ethernet frame Ethernet frame Preamble + SFD Transport of a Preamble + SFD MAC DA combination of antenna MAC DA MAC SA carriers (2G/3G/4G/5G IQ MAC SA data can be pre- EthType processed, compressed, or Ethtype unmodified) OBSAI frames unchanged RoE header-> length, AxC RoE header-> length, ID, FrameNum, Type = IQ SeqNum, type = structure Data/VSD/C&M, sample size, etc. agnostic, etc. Transparent vendor- specific data (transport CPRI frames unchanged only) RoE payload RoE payload Inter-packet GAP Inter-packet GAP Transparent C&M data New transport frames (transport only) unchanged Figure 1.35 RoE encapsulation: RoE structure aware and agnostic mappers [77]. considered implementing a structure-aware mapper for CPRI with well-defined encapsula- tion procedure. One can therefore distinguish between a simple tunneling mapper for the former use case and the structure-aware mapper for CPRI. There is also a structure-agnostic mapper in the specs which offers a middle ground for efficiency and complexity relative to the other mappers. Several use cases of RoE can be considered including aggregation of multiple CPRI streams from a number of RRHs to a single RoE link to the BBU pool, or a native edge-to-edge RoE connection from the RRH directly to the BBU pool. The RoE will logically add a new switching/aggregation node between the baseband pool and the radio resources. IEEE 1914.1 Next-Generation Fronthaul Interface The fronthaul packet transport enables implementation of critical 4G/5G technologies such as massive MIMO, CoMP transmission and reception, and scalable centralized/virtual RAN functions. Current ne