A system on chip (SOC) is a monolithic unit that performs a complex function, such as a personal computer, radar receiver, or cellular phone. Systems on chip are assembled using high-level components, such as processors, controllers, and memory arrays. The communication scheme among these components is key to delivering the desired performance within the prescribed energy consumption budget. For this reason, a large research effort is addressing the design and optimization of on-chip communication. Techniques borrowed from networking technologies are carried over to microelectronic design but have to cope with the advantages and limitations of the manufacturing technology for integrated circuits.