Photonic core node based on a 2.56-Terabit/s opto-electronic switching fabric

This paper proposes Photonic Core Node based on a 2.56-Terabit/s opto-elect ronic switching fabric, which can economically handle the rapidly increasin g multimedia traffics, such as Internet traffic. We have successfully devel oped the first prototype of Photonic Core Node. The prototype consists of a single-stage full-crossbar opto-electronic switching fabric, super-packet buffers for input queuing, and a desynchronized-round-robin scheduler. The switching fabric is upgradable up to 2.56 Tb/s, and employs wavelength-divi sion-multiplexing techniques, which dramatically reduce the total number of optical switching elements down to one-eighth the number of those used in a conventional switching fabric. The super-packet buffer assembles 16 ATM c ells routed to the same output port into a single fixed-length packet. The super-packet-switching scheme drastically reduces the overhead of optical s witching from 32 to 2.9%, although it tends to decrease effective throughpu t. The desynchronizsd-round-robin scheduler maintains nearly 100% effective throughput for random traffic, recursively resolving the contention of con nection requests in one scheduling routine while keeping fairness in a roun d robin manner. The proposed Photonic Core Node can accommodate not only AT M switching but also WDM optical path grooming/multiplexing, and IP routing by using IP input buffer interfaces, because optical switches are bit-rate /format-independent.