The FTλ - FRλ AWG network: a practical single-hop metro WDM network for efficient uni-and multicasting

Single-hop WDM networks with a central passive star coupler (PSC), as well as single-hop networks with a central arrayed-waveguide grating (AWG) and a single transceiver at each node, have been extensively studied as solutions for the quickly increasing amounts of unicast and multicast traffic in the metropolitan area. The main bottlenecks of these networks are the lack of spatial wavelength reuse in the studied PSC based networks and the single transceiver in the studied AWG based metro WDM networks. In this paper we develop and evaluate the FT^λ-FR^λ AWG network, which is based on a central AWG and has arrays of fixed-tuned transmitters and receivers at each node. Transceiver arrays are a mature technology, making the proposed network practical. In addition, the transmitter arrays allow for high speed signaling over the AWG while the receiver arrays relieve the receiver bottleneck arising from multicasting in conjunction with spatial wavelength reuse on the AWG. Our results from probabilistic analysis and simulation indicate that the FT^λ-FR^λ AWG network gives particularly good throughput-delay performance for multicast traffic with small multicast group sizes or localized destination nodes, as well as for a mix of unicast and multicast traffic.