Network on chip (NoC) paradigm replaces traditional, dedicated, and proprietary bus architectures of system on chip (SoC), and it is widely accepted by the system-level designers. In this chapter, an overview of the NoC design is presented in two different dimensions called macro-architectures and micro-architectures based on the design perspectives. Macro-architectures adopt the concept of computer network along with new innovations in topologies, protocols, and routing algorithms and so on whereas micro-architectures involve in the development of schedulers, arbiters, routers, and network adapter with existing or new concepts. From the comparison result, most of the NoC prototypes are developed with 2-D mesh architecture with packed switched concept. Apart from mesh architectures, some of the complex and hybrid concepts are also developed and discussed in this chapter.