Realizing Dynamic Optical Networking

Electronic asynchronous packet switching has been developed since the early 1960s and now, at the dawn of the 21 century, it is a well-understood technology. On the other hand, all-optical packet switching, a major candidate for the realization of dynamic optical networking, is a new technology, currently under-going research and development. In this paper we show that the transition from electronic to optical is not as straightforward as one would like to think. The main thesis of this paper is that the transition to dynamic all-optical switching will require changing the current asynchronous packet switching paradigm. This is shown by focusing the analysis on the simple problem of optical memory, while not considering the more complex problems associated with optical packet header processing and switching as if they had been resolved – which is indeed not the case. In order to evaluate optical memory, various comparative measures are used. For example, much more glass (Silicon) is needed for optical memory versus electronic memory, in fact a factor of 1 million! If we assume shrinking of Silicon circuitry by a factor of two every 18 months, the transition to optical packet switching will translate into reversing Moore’s law by 30 years. It will be shown that a common time reference (CTR) is needed for realizing the optical random access memory (O-RAM) required for dynamic optical networking. Furthermore, it is shown that by using coordinated universal time (UTC a.k.a. GMT) CTR can be globally distributed, then it is possible to (globally) distribute the O-RAM and, consequently, to realize a new dynamic optical networking architecture called Fractional Lambda Switching (FλS), that additionally, does not require optical header processing.