Network-on-Chip

To meet the growing computation-intensive applications and the needs of low-power, high-performance systems, the number of computing resources in single-chip has enormously increased, because current VLSI technology can support such an extensive integration of transistors. By adding many computing resources such as CPU, DSP, specific IPs, etc to build a system in System-on-Chip, its interconnection between each other becomes another challenging issue. 

Network ON Chip

In most System-on-Chip applications, a shared bus interconnection which needs an arbitration logic to serialize several bus access requests, is adopted to communicate with each integrated processing unit because of its low-cost and simple control characteristics. However, such shared bus interconnection has some limitation in its scalability because only one master at a time can utilize the bus which means all the bus accesses should be serialized by the arbitrator. Therefore, in such an environment where the number of bus requesters is large and their required bandwidth for interconnection is more than the current bus, some other interconnection methods should be considered.

Such scalable bandwidth requirement can be satisfied by using on-chip packet-switched micro-network of interconnects, generally known as Network-on-Chip (NoC) architecture. The basic idea came from traditional large-scale multi-processors and distributed computing networks. The scalable and modular nature of NoCs and their support for efficient on-chip communication lead to NoC-based system implementations. Even though the current network technologies are well developed and their supporting features are excellent, their complicated configurations and implementation complexity make it hard to be adopted as an on-chip interconnection methodology. In order to meet typical SoCs or multi-core processing environment, basic module of network interconnection like switching logic, routing algorithm and its packet definition should be light-weighted to result in easily implemental solutions.