16 - Optical burst and packet switching

Abstract

This chapter discusses optical burst switching (OBS) and optical packet switching (OPS) technologies and examines their roles in future optical networks, covering the roles of optical circuit, burst, and packet switching systems in optical networks, as well as their respective benefits and trade-offs. OPS and OBS technologies seek powerful combinations of the vast optical bandwidth and the agile subwavelength granularity by switching and routing packets and bursts directly in the optical layer. OBS offers best-effort burst transport and switching with one-way signaling so that high network utilization for bursty traffic can be achieved. OPS requires fast switching speeds (in the nanosecond range) to be effective. Recent advances in optical header (label) processing and optical switching led to asynchronous and variable-length OPS with contention resolution in wavelength, time, and space domains at nanosecond switching speeds. Unlike electronic packet switching routers, optical routers can exploit the wavelength domain to greatly reduce the buffer requirement and to discard store-and-buffer architecture involving packet processing in the data plane. A description is given of the networking architecture/protocols, systems, and technologies pertaining to optical burst and packet switching. Optical label switching technology is introduced, which provides a unified platform for interoperating optical circuit, burst, and packet switching techniques. In addition to the reduced complexity and power requirements in optical label switching (OLS) routers resulting from significantly reduced high-speed electronic processing in the data plane, further advances in integrated optoelectronic technologies may eventually allow chip-scale integration of OLS routers for the agile, robust, and high-performance Internet in the future.