All-optical MAC protocol for Gbits/sec fiber optic LANs/MANs

This paper proposes a MAC protocol for 2D grid networks, termed slotted grid protocol (SGP), for high speed LANs/MANs. To support high speed transmission and all- optical operation, intermediate routing and buffering is avoided. SGP combines the linear optical network concepts with 2D grid topology. It employs prefixed slotting and routing mechanisms, consequently resulting in scalable, all- optical or almost-all-optical techniques that results in high performance. SGP consists of two layers. The lower layer is slotted ring based protocol which employs two uni- directional trains to transport the packets along each of the merged rings which connect a group of nodes in the network. The upper layer is a token driven protocol which is to control the merging process so that al nodes are involved in the transmission simultaneously and every node can get a chance to work as a merging node. Multiple-queue strategy is adapted to realize the one-cycle full inter-connection on a unidirection ring. The multiple-queue strategy makes also the benefits for balancing the traffic load of the network, and for eliminating the head-queue effects. Consequently extendable capacity of the network and wider effective traffic load range are achieved based on the same node configuration and network configuration as that of the linear protocol, such as DQDB. The primary properties of the SGP are modeled and analyzed based on polling system principles. Simulation results are presented in this paper, which includes the comparison of the performance of SGP with that of DQDB.