An efficient WDM architecture with a wavelength-distributed synchronization protocol

In this paper we propose an efficient WDM architecture based on the MultiNet scheme, which is easier to implement and shows improved performance. The proposed architecture provides many desirable features such as a simple implementation of high bandwidth, low latency multicasting and broadcasting, lack of slow tunable components, and a simple protocol without a separate control channel which can be implemented in hardware. A novel hardware-based distributed synchronization protocol is proposed, which makes communications on individual WDM channels independent of each other while removing the need for defined propagation delays on waveguides. The new communication protocol is tell-and-go which makes it suitable for wide area networks. The protocol also allows an easy implementation of a packet loss avoidance scheme. Two new wavelength arbitration schemes are proposed to simplify wavelength assignment to nodes in a group. One is based on pre-allocation of transmission cycles to group members, while the other utilizes additional information transmitted during the pretransmission coordination phase. The simple hardware-implementable protocol minimizes the communication overhead by reducing the average length of a transmission cycle. A scheme for efficient handling of bursty traffic is proposed in which a node can receive simultaneous independent bursts on multiple wavelengths.