222 ITU‐T's Technical Reports and Specifications Figure 2 – Multi‐tier SSC ICT meta‐architecture2 A smart sustainable city can be also considered a system comprising subsystems and, its ICT architecture (as depicted in Figure 3), where each subsystem addresses a different smart sustainable city service category. Finally, with regard to its technical definition, it has been seen from different views. Figures 4 and 5 demonstrate the communication view of the SSC ICT architecture, from a physical and an information flow perspective respectively. Please note that both perspectives of this view are multi‐tier. Figure 3 – Subsystems of SSC ICT architecture2 ____________________ 2 According to Technical Specifications on “Setting the framework for an ICT architecture of a smart sustainable city”. Transport ation services.E‐governm ent services.E‐business services.Safety and Emergen cy services.Smart health services.Tourism services.Educatio n services.Smart Building.Waste manage ment services.Smart Energy services.Smart water services.