ITU‐T's Technical Reports and Specifications 927 3. Information and communication technology (ICT): ICT framework, architecture and information model; network and information security, availability and resilience; application and support layer; data layer; communication layer; sensing layer. 4. Buildings and physical infrastructure: urban planning; low carbon design and construction; intelligent building systems; building information modelling (BIM); traffic systems; urban pipeline network. In addition, it is important to develop a set of definitions for key terms relating to smart sustainable cities within and across each of these four categories of standards.