ecting to multiple RRHs, or in a central IEEE 1914.1: Standard for packet-based fronthaul transport networks (http://sites.ieee.org/sagroups-1914/ p1914-1/). 84 Chapter 1 FH-I (CPRI) FH-II (RoE) FH-II (Ethernet) RoE mapper aggregator and aggregator Case 1 Subclass 1 (100 ust Subclass 2 (1 ms) Subclass 3 (10 ms) Case 2 Subclass 1 (100 us) Subclass 2 (1 ms) Transport connection L1 aggregation blocks Subclass 3 (10 ms) L2 aggregation blocks eNB/gNB blocks URLLC FH-III-> CPRI/eCPRI/ Ultra-low latency transport Low latency transport Subclass 0 (50 us) Medium latency transport Subclass 1 (100 us) Subclass 2/3 (1/10 ms) Subclass 1 (100 us) Subclass 2/3 (1/10 ms) Subclass 3 (10 ms) Figure 1.37 Next-generation fronthaul: CPRI-over-Ethernet for LTE and NR 78]. office. These networks must be able to transport 5G flows with heterogeneous traffic pro- files. The traffic profiles may consist of traditional backhaul IP traffic, several different 3GPP functional split options traffic profiles, application traffic with varying latency needs, or non-IP CPRI TDM traffic. The transport network has to be able to serve all traffic pro- files with vastly different service-level requirements in the same transport network infra- structure [78]. The transport network dedicated to 5G services is hierarchical, which means it comprises different domains and progressively aggregates signals from RRHs, at one end and up to the packet core at the other end. The support of multi-level functional split, results in a logi- cal partitioning where more fronthaul segments and a backhaul segments may be identified. Fig. 1.37 depicts a generic model for converged fronthaul/backhaul network, where the 5G Network Architecture 85 following segments are identified: Fronthaul-I (NGFI-I), connecting the RU to a DU; Fronthaul-II (NGFI-II), connecting the DU to a CU; and Backhaul (BH), connecting the CU to the packet core elements. The NGFI reference architecture assumes all network deploy- ment scenarios can leverage the same transport network infrastructure.