# Sustainable and Reliable Information and Communication Technology for Resilient Smart Cities
## 1 Introduction  
Smart cities and communities are at the forefront of innovation, research and development in modern societies. Subsequently, we use the term smart city as shorthand for smart city and community. As of 2020, more than 50% of the world population lives in cities [1], with predictions for a dramatic increase in the percentage of urban populations in the coming years [1]. Hence, there is an urgent need to optimize the processes within a city/community and to push for new eco-systems generating novel business and operational models for increasing the quality of life for citizens, whilst at the same time reducing costs and improving the city/community processes and operations. Thereby, ICT (Information and Communication Technologies) plays a vital role in enabling such eco-systems, given that they will emerge around the notion of data and information gathering, and making these data and information available across multiple domains towards the combination and exploitation of synergies amongst various aspects of urban business and everyday life. A smart city naturally emerges around an urban data platform, which consolidates various data sources across an urban eco-system. Indeed, the data sources can be versatile, including static data--e.g., governmental data, Open Data in general, and any sort of city data and information that do not constantly change in value/parameters--and dynamic data, e.g., continuous real-time data like sensor/Internet of Things (IoT) data, global positioning data, etc. In order to facilitate such a data driven approach, variouscomponents, network segments, and computing nodes from different silos and domains need to interplay efficiently towards enabling a data driven smart city. This includes sensors generating and sending data over belonging gateways, which in turn forward the sensor data over telecom/Internet type of networks to data nodes at the network edge or data centers in the cloud. In addition, different services and applications--including mobile and embedded--utilize the data, analyze them and generate added value for end users, citizens, city decision makers and further stakeholders within an urban environment. Along these considerations, it is very important to establish a holistic approach to the ICT in a smart city. Such a holistic approach should serve as a blueprint for establishing an urban ICT infrastructure and should enable the creation of dynamic and versatile eco-systems of large industry, small-mid size enterprises, start-ups, the public sector, open source communities, non-governmental organizations, applied research institutes, universities and city administrations. Such a holistic approach can be designed based on a reference architecture, which leans on other reference architectures coming from domains such as telecommunications (e.g., ISO/OSI (Open Systems Interconnection [OSI] Reference Model of the International Organization for Standardization [ISO]), TMN (Telecommunications Management Network defined by the International Telecommunication Standardization Sector) and others) or Internet data-based communication (e.g., TCP/IP (Transmission Control Protocol/Internet Protocol defined by the Internet Engineering Task Force [IETF]) and others). Such reference models have enabled the rapid growth of voice and data communication across the world and have led to one of the most impressive success stories of human kind--the Internet. Indeed, as the Internet and the telecommunication domain in general has proven to have developed in a sustainable and resilient way, we envision the same for the emerging ICT infrastructures within cities and communities that will serve as the backbone of future societies.