ed Consumer 2-layer DL, 1-layer UL 10 MHz 538 Mbps DL 302 Mbps DL 404 Mbps DL indoor 269 Mbps UL 151 Mbps UL 202 Mbps UL Consumer 4-layer DL, 2-layer UL 20 MHz 2.15 Gbps DL 1.21 Gbps DL 1.61 Gbps DL 1.07 Gbps UL 0.61 Gbps UL 0.81 Gbps UL Outdoor 4-layer DL, 4-layer UL 20 MHz 2.15 Gbps DL 1.21 Gbps DL 1.61 Gbps DL 2.15 Gbps UL 1.21 Gbps UL 1.61 Gbps UL Chapter 3 Hardware system dimensioning 115 latency increases significantly when accounting for large (sets of) packets, for example as needed for L2/L1 interfacing. A high-performance deployment is expected to use 10GbE + link speeds. In addition to the serialization latency, we need to account for the physical transmission latency through the medium. The speed of light is approximately 3.34 microseconds/km but due to refraction in the fiber, fiber speeds are slightly lower at approximately 4.9 microseconds/km. Given a 'typical maximum' distance between DU and RU of 10s of km, the physical transmission latency through the medium can dominate the overall system latency. Cost of Ethernet switching/routing in the fronthaul. As we indicated earlier, as a rule of thumb and omitting queueing delays caused by congestion, consider the following latencies <1 microsecond latency for a latency-optimized (cut-through) Ethernet switch-the most likely option for fronthaul applications. <10 microseconds latency for a store-and-forward Ethernet switch. 10-100 microseconds latency for a software implemented switch or router function running on high-performance CPU core (example: DPDK based implementations). This latency includes IPSec or other tunneling cost. RU termination latency which is expected to be like the DU termination latency. End-to-end latencies over Ethernet in a virtualized, software centric world is measured below 100 microseconds but this can be optimized in a nonvirtualized environment or more hardware centric implementations to 10 or lower microseconds. Distributed unit internal IO Bandwidths between various components inside the DU need to be understood well when