Abstract: A modular optical switch includes a set of optical switch modules connected in a mesh, a master controller for the whole optical node and a switch-module controller for each of the optical switch modules. The optical switch modules receive optical signals from, and transmit optical signals to, edge nodes based on connection requests received from the edge nodes. The master controller acts to select a path, using a simple or compound time-slot matching process, through the mesh of switch modules for each optical signal related to a connection request. Advantageously, the optical switch modules are fast switching, enabling the use of time-sharing schemes such as TDM, and the modular optical core node is made practical by efficient path selection at the master controller. A hybrid modular switch may include both optical and electronic switch modules, a master controller, and a switch-module controller for each of the switch modules.

Abstract: A packet switching system of an access capacity scalable to multiple petabits per second is disclosed. A multiplicity of switch units, each of a relatively small dimension, is organized into orthogonal sets of switch units and the switch units of each set are cyclically interconnected through a respective dual rotator. Each switch unit has a contention-free switching mechanism and is coupled to a same number of dual rotators. Each switch unit has a switch-unit controller configured to route data received from external data sources to external data sinks coupled to any other switch unit by communicating with at most one switch-unit controller of an intermediate switch unit.

Abstract: Multiple switch planes, each having meshed bufferless switch units, connect source nodes to sink nodes to form a communications network. Each directed pair of source and sink nodes has a first-order path traversing a single switch unit in a corresponding switch plane and multiple second-order paths each traversing two switch units in one of the remaining switch planes. To reduce processing effort and minimize requisite switching hardware, connectivity patterns of source nodes and sink nodes to the switch planes are selected so that each pair of source node and sink node connects only once to a common switch unit. Widely-varying flow rates may be allocated from each source node to the sink nodes. To handle frequent changes of flow-rate allocations, in order to follow variations of traffic distribution, a high-throughput scheduling system employing coordinated multiple scheduler units is provided in each switch plane.

Abstract: The invention provides a method and network communication equipment for low latency loss-free burst switching. Burst-transfer schedules are determined by controllers of bufferless core nodes according to specified bitrate allocations and distributed to respective edge nodes. In a composite-star network, burst schedules are initiated by any core node. Burst formation takes place at source edge nodes and a permissible burst size is determined according to an allocated bitrate of a burst stream to which the burst belongs. The permissible burst size is subject to constraints such as permissible burst-formation delay, a minimum guard-time requirement, and permissible delay jitter. A method of control-burst exchange between each edge node and each bufferless core node enables burst scheduling, time coordination, and loss-free burst switching. Both the payload bursts and control bursts are carried by optical channels connecting the edge nodes and the core notes.

Abstract: Methods and apparatus for determining encoding parameters of an encoder or a transcoder which yield an encoded signal of optimal measurable properties are disclosed. For a video signal, the encoding parameters may include quantization granularity, a measure of display resolution, and a frame rate. The measurable properties of an encoded signal may include a fidelity index, a relative size, and a relative flow rate. Reference data records quantifying properties of sample signals encoded according to experimental sets of encoding parameters are used to define parameters of conjectured analytical functions characterizing the encoding or transcoding functions. The analytical functions are then used to generate granular tables of estimated measures of encoded-signal properties. A fast search mechanism relies on the granular tables, together with sorted arrangements of the granular tables, to determine, in real-time, preferred encoding parameters for multimedia data streams received at an encoder or a transcoder.

Abstract: Methods of optimal encoding of signals to be compatible with characteristics of target receivers while meeting constraints pertinent to sizes of encoded signals or capacities of paths communicating signals to the target receivers are disclosed. The methods are based on analytical modeling of the encoding process guided by experimental data relating measured performance indicators of encoded signals of diverse classifications to respective encoding parameters. A computationally-efficient technique is devised to determine optimal encoding parameters based on pre-processed data derived from the analytical models. The methods may be implemented at an encoder of original signals or a transcoder of pre-encoded signals.

Abstract: In a communication network comprising nodes and links between the nodes, a controller node disseminates link state information. A nodal routing table exists at each node comprising routes between pairs of nodes. The nodal routing table is either populated by the given node based on network information received from the controlling node or populated at the controlling node and received by the given node. Each node receives heartbeat signals from its neighboring nodes. An unexpected delay between heartbeat signals may be perceived as a failure of a link. The perceived failure of that link is reported by the perceiving node to the controlling node. Upon receiving link failure information from a node, the controlling node may determine a subset of nodes in the network influenced by the link failure and indicate the link failure to the determined subset of influenced nodes.

Abstract: A modular optical switch includes a set of optical switch modules connected in a mesh, a master controller for the whole optical node and a switch-module controller for each of the optical switch modules. The optical switch modules receive optical signals from, and transmit optical signals to, edge nodes based on connection requests received from the edge nodes. The master controller acts to select a path, using a simple or compound time-slot matching process, through the mesh of switch modules for each optical signal related to a connection request. Advantageously, the optical switch modules are fast switching, enabling the use of time-sharing schemes such as TDM, and the modular optical core node is made practical by efficient path selection at the master controller. A hybrid modular switch may include both optical and electronic switch modules, a master controller, and a switch-module controller for each of the switch modules.

Abstract: A one-dimensional circulating switch may be defined by connections between several switch modules and one or more temporal cyclic rotators. Where a switch module that is part of a first one-dimensional circulating switch is also connected one or more temporal cyclic rotators that define a second one-dimensional circulating switch, a two-dimensional circulating switch is formed. A two-dimensional circulating switch is flexible and may scale to capacities ranging from a few gigabits per second to multiple Petabits per second.

Abstract: Multiple switch planes, each having meshed bufferless switch units, connect source nodes to sink nodes to form a communications network. Each directed pair of source and sink nodes has a first-order path traversing a single switch unit in a corresponding switch plane and multiple second-order paths each traversing two switch units in one of the remaining switch planes. To reduce processing effort and minimize requisite switching hardware, connectivity patterns of source nodes and sink nodes to the switch planes are selected so that each pair of source node and sink node connects only once to a common switch unit. Widely-varying flow rates may be allocated from each source node to the sink nodes. To handle frequent changes of flow-rate allocations, in order to follow variations of traffic distribution, a high-throughput scheduling system employing coordinated multiple scheduler units is provided in each switch plane.

Abstract: A scalable router-switch that grows from a capacity of a few gigabits per second to hundreds of terabits per second is disclosed. In one embodiment, the router-switch comprises a plurality of switch units arranged in a plurality of combinations. Within each combination, each switch unit cyclically connects to each other switch unit to form a contention-free temporal mesh. Each switch unit belongs to a number of combinations and any two combinations have at most one switch unit in common. The router-switch further includes a distributed-control system which comprises an outer controller associated with each of the switch units and an inner controller associated with each combination. The structural simplicity significantly simplifies the operation and control of the router-switch.

Abstract: A balanced, bufferless switch scalable to high capacities and requiring less processing effort with less internal fabric expansion in comparison with prior-art switches. The balanced, bufferless switch employs a pre-switching or post-switching balanced-connector.

Abstract: A packet switch that scales gracefully from a capacity of a fraction of a terabit per second to thousands of terabits per second is disclosed. The packet switch comprises edge nodes interconnected by independent switch units. The switch units are arranged in a matrix having multiple rows and multiple columns and may comprise instantaneous or latent space switches. Each edge node has a channel to a switch unit in each column and a channel from each switch unit in a selected column. A simple path traversing only one of the switch units may be established from each edge node to each other edge node. Where needed, a compound path comprising at most two simple paths may be established for any edge-node pair. In a preferred configuration, the switch units connect at input to orthogonal sets of edge nodes. A distributed control system expedites connection-request processing.

Abstract: A switching system formed of a number of nodes interfacing with external network elements and interconnected through a number of independent switches is disclosed. The switches are arranged into a set of primary switches, a set of secondary switches, and a set of tertiary switches and each node connects to a respective primary switch, a respective secondary switch, and a respective tertiary switch. The connection pattern of nodes to switches is selected so that any set of nodes connecting to any primary switch, any set of nodes connecting to any secondary switch, and any set of nodes connecting to any tertiary switch are mutually orthogonal. A distributed control system sets a path from any node to any other node traversing at most two switches. The switching system may serve as a large-scale data-switching center or a geographically distributed network.

Abstract: A one-dimensional circulating switch may be defined by connections between several switch modules and one or more temporal cyclic rotators. Where a switch module that is part of a first one-dimensional circulating switch is also connected one or more temporal cyclic rotators that define a second one-dimensional circulating switch, a two-dimensional circulating switch is formed. A two-dimensional circulating switch is flexible and may scale to capacities ranging from a few gigabits per second to multiple Petabits per second.

Abstract: A packet switch that scales gracefully from a capacity of a fraction of a terabit per second to thousands of terabits per second is disclosed. The packet switch comprises edge nodes interconnected by independent switch units. The switch units are arranged in a matrix having multiple rows and multiple columns and may comprise instantaneous or latent space switches. Each edge node has a channel to a switch unit in each column and a channel from each switch unit in a selected column. A simple path traversing only one of the switch units may be established from each edge node to each other edge node. Where needed, a compound path comprising at most two simple paths may be established for any edge-node pair. In a preferred configuration, the switch units connect at input to orthogonal sets of edge nodes. A distributed control system expedites connection-request processing.

Abstract: A scalable router-switch comprises a plurality of switch units each having consolidation means for data disassembling and reassembling. The switch units are arranged into switch modules and the switch units of each switch module are interconnected through a dual rotator to form a contention-free temporal mesh.

Abstract: A network comprising a large number of electronic edge nodes interconnected through bufferless optical switch planes so that a signal from any edge node to any other edge node traverses only one switch plane scales to a capacity of hundreds of petabits per second while providing global geographic coverage. Each edge node is time-locked to each optical switch plane to which it connects to enable loss-free time-sharing of the network core despite the absence of buffers in the core. In an alternate implementation, a relatively small number of electronic switch units may be employed in a predominantly-optical core. In addition to scalability and high performance, the simple structure of the network significantly simplifies addressing and routing.

Abstract: Independent switches arranged into multiple switch planes interconnect nodes coupled to data sources and sinks to form a switching node which scales gracefully from a capacity of a fraction of a terabit per second to hundreds of terabits per second. The switches of each switch plane are arranged in a matrix. Each node connects to an inlet of a selected switch in each column and an outlet of a selected switch in each row in each switch plane. A route set for each directed node pair includes simple paths, each traversing one switch, and compound paths, each traversing two switches. The connectivity of nodes to switches ensures that each switch may be selected to handle data flow of any directed node pair and that all simple paths leading to any node traverse switches which receive data from mutually orthogonal sets of nodes. This feature equalizes flow rates through the switches.

Abstract: A network comprising a large number of electronic edge nodes interconnected through bufferless optical switch planes so that a signal from any edge node to any other edge node traverses only one switch plane scales to a capacity of hundreds of petabits per second while providing global geographic coverage. Each edge node is time-locked to each optical switch plane to which it connects to enable loss-free time-sharing of the network core despite the absence of buffers in the core. In an alternate implementation, a relatively small number of electronic switch units may be employed in a predominantly-optical core. In addition to scalability and high performance, the simple structure of the network significantly simplifies addressing and routing.