gNB transmit at an average rate (say, 0.2 of the peak rate) simultaneously. Single-peak, all-average takes the higher requirement from the two: either one sector peak or the sum of all sector average rates. Single-peak, all-but-one average refers to a single sector transmitting at the peak rate and all the others at an average rate. All sectors transmitting simultaneously at the maximum rate results in the all-peak scenario, which is the rather theoretical maximum rate. 9.2.3 Distribution Tier The previous method gives an estimate for the capacity needed for the first mile link (single site). When traffic is combined from multiple access links in the distribution tier (or on any hub site), the statistical multiplexing gain reduces the capacity needed on the common uplink. The amount of gain depends on the traffic patterns, number of sites, and whether those sites experience peak traffic condition at the same time. Typically, sites in business areas are busy during working hours, while residential areas produce traffic peaks in the evenings. When multiple sources queue for service such as egress port transmission, the delay increases rapidly when the utilization on the link grows above 70-80%. Thus, network links cannot be loaded up to full nominal capacity without causing delay, which is expe- rienced especially by flows in the lowest priority queues. 9.2.4 Backhaul and High Layer Fronthaul Capacity For 5G TDD duplexing, the capacity in the downlink (DL) or uplink (UL) direction also depends on the DL/UL ratio; here, 80% DL and 20% UL is assumed, SO any symmetrical transport link will be downlink limited. The transport protocol overhead in the examples include IPv6, IPsec, and Ethernet overhead with VLANs (virtual local area networks). The overhead in the downlink direction is 15-20% when the packet mix is dominated by large user packets, which is typically the case. In the uplink direction, the overhead is larger, assuming smaller user packets (such as TCP acknowledgements). Nevertheless, the downlink imposes hi