Optical packet switching nodes and networks.

摘要

The exponential growth of Internet traffic has created enormous demands for increase routing capacity and bandwidth. The advent of wavelength division multiplexing (WDM) has enhanced tremendously the transport of large data volume. However, there has been no comparable breakthrough in router technology to route the voluminous data present in the Internet. Optical burst switching (OBS) can be an efficient technique for the optical core routing. The new generation of routers should be scalable, support native Internet protocol (IP) as well as legacy networks such as asynchronous transfer mode (ATM), guarantee a short deterministic delay, and offer quality of service (QoS) and multicasting capabilities. An all-optical technique is an excellent candidate for developing the next generation routers.; The transport of Internet protocol (IP), which is done today by ATM or synchronous optical networks (SONETs) can be done more cheaply and efficiently by putting IP directly over WDM. IP over WDM can achieve at a higher data rates, and this scheme is more scalable than either IP over ATM or IP over SONET schemes. However, framing and protocol techniques for IP over WDM, which incorporate the management and restoration functions, are required and still under development.; An optical IP router consists of optical switching matrices, wavelength converters, and buffers, combined with electronic IP address look-up and scheduling and control units. Different designs of optical buffer are discussed and a new algorithm is proposed for scheduling IP packets to avoid excess load introduced by the discrete granularity of fiber delay lines (FDLs).; Four different buffer control algorithms are proposed. The tele-traffic performance of optical routers under self-similar traffic is simulated for each of the algorithms proposed. We find that a good control algorithm can lower the packet loss rate. Also, when the self-similarity of the IP traffic is lower, the packet loss rate is reduced under the same traffic load.; Different single-stage optical switching matrices based on semiconductor optical amplifiers (SOAs) and FDL buffers, and a two-stage switching architecture, are discussed. We perform the theoretical and simulation analysis of the packet loss rate for these architectures and study the throughput performance of the two-stage architecture. The packet loss rate decreases as the number of wavelengths used to route the IP packets increases for fixed input connectivity and traffic load.; Burst classification and formation are important functions for an OBS network. In the manuscript "On traffic shaping for IP optical burst routers," we develop a new burst assembly algorithm. This algorithm can aggregate multiple IP packets into an optical burst efficiently, limiting the assembling delay. It also reduces the self-similarity of the traffic, thus improving the tele-traffic performance of the OBS network.