Future healthcare systems and organizations demand huge computational resources, and the ability for the applications to interact and communicate with each other, within and across organizational boundaries. This chapter aims to explore state-of-the-art of the healthcare landscape and presents an analysis of networked healthcare systems with a focus on networking traffic and architectures. To this end, the relevant technologies including networked healthcare architectures and performance studies, Health Level 7 (HL7), big data, and cloud computing, are reviewed. Subsequently, a study of healthcare systems, applications and traffic over local, metro, and wide area networks is presented using multi-hospital cross-continent scenarios. The network architectures for these systems are described. A detailed study to explore quality of service (QoS) performance for these healthcare systems with a range of applications, system sizes, and network sizes is presented. Conclusions are drawn regarding future healthcare systems and internet designs along with directions for future research.