This talk discusses communication technologies and network architectures for Internet of Things and Smart Cities scenarios. In particular, the adoption of current wireless communication technologies, such as LoRa (Long Range), Sigfox, 4G and IEEE802.15.4, for the provision of public smart-lighting services is addressed, highlighting their pros and cons. The outcome of a measurement campaign concerning the coverage of the LoRa technology in a real urban environment is presented, showing that star networks, such as those established by LoRa devices, are not suited for such service owing to possible coverage gaps. A large-scale deployment of a smart-lighting infrastructure in an Italian municipality is also presented, which is based on the IEEE802.15.4 short-range communication technology. It consists of around 3,000 luminaries deployed in an urban area of 11 square kilometers, which established a mesh network among them in order to exchange information in a multi-hop fashion with the control center. The feasibility of this solution is discussed, and the economic impact of the smart-lighting service is also emphasized.