Abstract: A system for simultaneously transmitting and receiving multiple data messages on a unidirectional ring having a plurality of nodes coupled thereto is described. This technique utilizes a medium access (MAC) protocol for a multi-gigabit-per-second local-area optical wavelength division multiplexed (WDM) network that is particularly well suited for high-performance computing environments that need a network that provides quality of service and the ability to enforce service level agreements. The protocol uses an asynchronous, unslotted, tokenless, and collision-free access scheme that is arbitrated by a centralized scheduler. The embodiment is based on a folded-bus unidirectional ring that is passively optically tapped by the nodes to both transmit data onto the network and to receive data from the network.

Abstract: A fiber-optic networking system that can survive a break in the fiber and restore full connectivity to all nodes in the network. The network can detect the presence of a cut in the fiber, locate the cut, recover from the cut, and restore the communication capacity that was available before the cut. The network is also capable of automatically determining the existence and identity of the nodes in the network, the distance of the node from the headend, and the executing procedures to handle both planned and unplanned (i.e., during a fault) removal of nodes from the network.

Abstract: A method and apparatus for a communications network that executes a medium access control (MAC) protocol that permits multiple access to a shared medium or shared switching fabric. The MAC protocol uses a BANDWIDTH_ALLOCATOR to regulate access to the network by sending a permission message to a NODE, allowing it to transmit to a specific set of NODEs for a specific length of time. The medium and switching fabric can carry one or more protocols, each of varying framing format and native bitrate. The switching fabric provides a connection-oriented bufferless data transport service that preserves frame ordering. An illustrative embodiment uses a slotted master/slave time-division multiplexed access (TDMA) scheme to allow flexible provisioning of network bandwidth.

Abstract: The present invention describes a system for providing quality of service (QoS) features in communications switching devices and routers. The QoS provided by this system need not be intrinsic to the communication protocols being transported through the network. Preferred embodiments also generate statistics with the granularity of the QoS. The system can be implemented in a single application-specific integrated circuit (ASIC), in a chassis-based switch or router, or in a more general distributed architecture. The system architecture is a virtual output queued (VOQed) crossbar. The administrator establishes policies for port pairs within the switch, and optionally with finer granularity. Frames are directed to unique VOQs based on both policy and protocol criteria. Policies are implemented by means of a scheduling engine that allocates time slices (minimum units of crossbar access).