Optical and electronic technologies for packet switching

Publisher Summary This chapter examines the potential role of both optical and electronic technologies in future high-capacity packet switches, beginning with an introduction to the functionality of routers and the key functional building blocks of high-capacity routers. A brief overview is provided of state-of-the-art routers, and the critically important consideration of power consumption in router design is highlighted in the chapter. The key physical layer building blocks in packet switches are buffers, interface components including interconnects, wavelength converters and regenerators, and switch fabrics or cross-connects. The most important consideration in the design of future high-capacity routers will be energy consumption and the associated heat dissipation problems. The energy bottleneck has become a major problem in the design of high-capacity electronic routers, and designers are looking for alternative design approaches for the future. It has long been recognized that the lack of a practical optical buffer technology is a major impediment to the development of optical packet switching. Recent theoretical results indicate that optical buffers might not need to have large capacity. A key conclusion of this chapter is that future generations of high-capacity routers might use more optical components and more optoelectronic components than today, particularly in interconnects.