Coupled reservation protocols for hierarchical single-hop photonic networks

Future photonic LANs and MANs may be based upon single-hop architectures using wavelength division multiplexing (WDM) and passive star coupling. However, single hop designs have been introduced which use a hierarchical structure employing simple wavelength routing functions. A salient feature of this type of network is that a set of wavelengths can be reused locally, while maintaining full single-hop connectivity through a different set of globally shared wavelengths. In such a network, wavelength routing divides the system into separate local and remote subnetworks, which may be accessed from each station by a single tunable transmitter. As a result, media access protocol operation can be implemented independently for each subnetwork, or it may be coupled between levels. These two options are investigated, focusing on remote subnetwork performance. Since global connectivity is achieved using a single set of remote wavelengths, it is important that they are efficiently used. The proposed protocols implement different forms of dynamic movable boundary TDMA, using various request/allocation mechanisms motivated by the channel controller approach. It is shown that, in such networks, remote channel efficiency can be improved significantly through a strong coupling of local and remote system operation