Interconnection structures for highly parallel systems

The interconnection network design space and directions of its potential evolution are discussed. Communications within highly-parallel systems can be classified in two categories: input/output (I/O)-related communications which involve the transfer of large blocks of data and take place across the memory hierarchy of the system; and communications which typically involve the transfer of small units of information needed for process execution. These two types of communication have distinctly different transfer characteristics, the former requiring primarily high-throughput while the latter very low latency. As the capabilities of processors increase, the system communication requirements become more stringent. The author examines interconnection network structures and trends in underlying network implementation technologies that are needed to meet this challenge