The above paper by L. Bhuyan and D.P. Agrawal (1984) described a hierarchical, all-optical wavelength division multiplexed (WDM) network that is being built to support the communication requirements of a large distributed shared memory system. Dynamically adaptable bandwidth allocation is supported, both within and between levels of the hierarchy, and is highly scalable through wavelength re-use at each hierarchical level. The mixed radix scheme introduced was used for processor numbering, but was not specified. The system was described in term of a time multiplexed access protocol, generalized to the multichannel WDM environment, which has static slot assignment that provides excellent throughput but long latencies due to cycle synchronization. The actual system implementation will use a hybrid WDMA strategy, which is collisionless, provides low latency support, dynamic bandwidth allocation within a hierarchical level, and a fast reliable broadcast.>

This paper introduces a hierarchical optical structure for processor interconnection and evaluates its performance. The architecture is based on wavelength division multiplexing (WDM) which enables multiple multi-access channels to be realized on a single optical fiber. The objective of the hierarchical architecture is to achieve scalability yet avoid the requirement of multiple wavelength tunable devices per node as with the WDM-based hypercube interconnection scheme. Furthermore, single-hop communication is achieved: a packet remains in the optical form from source to destination and does not require cross dimensional intermediate routing. The wavelength multiplexed hierarchical structure features wavelength channel re-use at each level, allowing scalability to very large system sizes. It employs acousto-optic tunable filters in conjunction with passive couplers to partition the traffic between different levels of the hierarchy without electronic intervention. A significant advantage of the proposed structure is its ability to dynamically vary the bandwidth provided to different levels of the hierarchy. The architecture is compared to a wavelength-flat architecture in terms of physical and performance scalability.>

The impact of the wavelength-tunable device switching latency on the performance of media access protocols for star-coupled wavelength-division-multiplexed (WDM) photonic networks is investigated. The effects of a reservation-base protocol (TDMA-C) and two preallocation-based protocols (I-TDMA* and I-SA) are compared. TDMA-C is control-channel based, with one WDM channel allocated to reserve access for data packet transmission on the remaining data channels. I-SA and I-TDMA* are designed for a network where channels are preallocated to the nodes for reception, with each node having a home channel it uses for all data packet receptions. The performance of the protocols is evaluated through discrete-event simulation is terms of network throughput, packet delay, and data channel utilization, with variations in the number of nodes and data channels, packet generation rate, data packet length, optical device switching latencies, and propagation delay.>

Media access control protocols for an optically interconnected star-coupled system with preallocated wavelength-division multiple-access channels are discussed. The photonic network is based on a passive star-coupled configuration in which high topological connectivity is achieved with low complexity and excellent fault tolerance. The channels are preallocated to the nodes with the proposed approach, and each node has a home channel it uses either for data packet transmission or data packet reception. The performance of a generalized random access protocol is compared to an approach based on interleaved time multiplexing. Semi-Markov analytic models are developed to investigate the performance of the two protocols. The analytic models are validated through extensive simulation. The performance is evaluated in terms of network throughput and packet delay with variations in the number of nodes, data channels, and packet generation rate.>

Introduces two hierarchical optical structures for processor interconnection and compares their performance through analytic models and discrete-event simulation. Both architectures are based on wavelength division multiplexing (WDM) which enables multiple multi-access channels to be realized on a single optical fiber. The objective of the hierarchical architectures is to achieve scalability yet avoid the requirement of multiple wavelength tunable devices per node. Furthermore, both hierarchical architectures are single-hop: a packet remains in the optical form from source to destination and does not require cross dimensional intermediate routing.>

This paper compares the performance of two time-division multiplexed media access protocols designed for star-coupled wavelength-division multiplexed (WDM) photonic networks. The TDMA-C protocol is reservation based: one WDM channel is used to reserve access for data packet transmission on the remaining data channels. Control channel access arbitration is achieved through time-division multiplexing, enabling all active nodes the opportunity to transmit once every control cycle. This approach significantly reduces the long synchronization delays typical of time-division multiplexing systems since the control cycle length is proportional to the control packet size rather than the data packet size. Every node in this system has one turnable transmitter and two receivers.>

Media access control protocols for an optically interconnected star-coupled system with pre-allocated WDMA channels are introduced and compared. The photonic network is based on a passive star-coupled WDM–based configuration with high topological connectivity and low complexity. The channels are pre-allocated to the nodes with this approach, where each node has a home channel that it uses either for all data packet transmissions or all data packet receptions. A home channel may be shared if the number of nodes exceeds the number of channels in the system. This approach does not require both tunable transmitters and tunable receivers. The performance of a generalized random access protocol is compared to a protocol based on interleaved time multiplexing. Both protocols are designed to operate in a multiple-channel multiple-access environment and require each node to possess a tunable transmitter and a fixed (or slow tunable) receiver. Semi-markov analytic models are developed to investigate the performance of the two protocols. The analytic models are validated through simulation and performance is evaluated in terms of network throughput and packet delay with variations in system parameters.