Architectural and perfonnance aspects of OFDM nodes for the future transport network

For the transport of the ever increasing traffic volume, an enhancement of the existing transport network will be required. For this purpose optical cross-connects and add/drop multiplexers based on the optical frequency division multiplexing (OFDM) principle will be added to the existing transport network. In this paper different OFDM node architectures are evaluated with respect to the influence of the size of the switching network on attenuation and cross-talk, the type of optical frequency converter and suitability for multicast connections, and other factors. Various scenarios for the interconnection of these optical cross-connects with the existing electrical cross-connects are discussed. For the individual optical cross-connect architectures and the interconnection scenarios, a study on the blocking probabilities for new optical connection requests was made, taking into account a suitable connection admission control mechanism and different channel hunting strategies. The performance evaluation showed that a savings of optical frequency converters in an optical cross-connect is possible compared to the nonblocking case, without deteriorating the performance significantly. However, other relevant topics such as connection management or implementation of the switching network become more complex.