“…For the RAN domain, the PNFs include spectrum, time, antenna, RRU pool, BBU pool, and CPU pool, etc, while VNFs contain digital filter, FFT/IFFT module, modulation/demodulation module, coding/decoding module, hybrid automatic repeat request (HARQ) function, MAC protocol, RLC protocol, and PDCP protocol, etc. [35], [36]. For the TN domain, the physical routers are the real hardware such as Huawei's router OTN9800, while the virtual routers are the ones generated by open source codes such as Open vSwitch (OVS) and Mininet [37], [38].…”