Abstract: A polyphase circulating switch includes switch modules interconnected through a multiplicity of rotators preferably arranged in complementary groups of opposite rotation directions. A polyphase circulating switch having a low switching delay is derived from a multi-rotator circulating switch by providing programmable rotators having adjustable relative rotator-cycle phases. A low delay high-capacity switch may also be constructed from prior-art medium-capacity rotator space switches with mutually phase-shifted rotation cycles. A network comprising several constellations of switch modules distributed over a wide geographic area, where the switch modules of each constellation are interconnected through a rotator assembly, is also disclosed. A rotator assembly may comprise an array of rotators and a master controller for data-transfer scheduling and time-coordination.

Abstract: A transit memory assembly of a rotator-based switching node is logically partitioned into two sections, one operated as a common-memory switch fabric and the other as a time-shared space-switch fabric. The composition of data received at input ports of the switching node determines adaptive capacity division between the two sections. Based on an indication of traffic type, a controller of at least one input port selects one of the two sections. The space-switch section enables scalability to a high transport capacity while the common-memory section enables scalability to a high processing throughput. The switching node includes rotators and a bank of transit-memory devices that facilitate the incorporation of any mixture of periodic, aperiodic, contention-free exclusive-access, concurrent-access, and multicast switching.

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 circulating switch comprises switch modules of moderate capacities interconnected by a passive rotator. Data is sent from a one switch module to another switch module either directly, traversing the rotator once, or indirectly through at least one intermediate switch module where the rotator is traversed twice. A higher capacity extended circulating switch is constructed from higher-capacity switch modules, implemented as common memory switches and having multiple ports, interconnected through a multiplicity of rotators preferably arranged in complementary groups of rotators of opposite rotation directions. A polyphase circulating switch having a low switching delay is derived from a multi-rotator circulating switch by providing programmable rotators having adjustable relative rotator-cycle phases. A low delay high-capacity switch may also be constructed from prior-art medium-capacity rotator space switches with mutually phase-shifted rotation cycles.

Abstract: A universal electronic switching node serves as an edge node in a high-capacity network with an optical core. The universal edge node may handle a variety of traffic classes and may control traffic admission, connection definition, connection routing and core node configuration. The provided capabilities significantly simplify network operation and control. The universal edge node includes input ports for receiving data streams, output ports for transmitting the data streams though the optical core, a switching fabric for communicating these data streams between input and output ports and a controller for controlling this communicating. In particular, the controller can select a route through the optical core, schedule the communication between input and output ports and adaptively allocate the bitrate of this communication.

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 fast optical switch is needed to realize an economical and scaleable optical-core network. In the disclosed optical switch, switching is effected by rapid wavelength conversion. Either channel switching, Time Division Multiplex (TDM) switching or both may be provided by the fast optical switch. The operation of the fast optical switch is enabled by a fast scheduler. The throughput of the optical switch may be increased through a process of bimodal pipelined connection-packing. An in-band exchange of control signals with external nodes may serve to minimize the control overhead. Such control signals may include time-locking signals and connection-requests. A modular structure may be configured to comprise several fast optical switches to yield a high-speed, high-capacity, fully-connected optical switch.

Abstract: A high capacity switching node comprises a lattice structure of low-latency switch units and a plurality of balanced connectors interfacing electronic edge nodes to diagonal subsets of said switch units. The edge nodes may be collocated with the switch units or remotely located. The switch units may be bufferless, having optical switch-fabrics for example, thus requiring a compound vacancy-matching process. Using switch units each of dimension 64×64, a fast switching node having a dimension of the order of 10,000×10,000 can be constructed. With a typical wavelength-channel capacity of 10 Gb/s, the fast-switching node would scale to a capacity of 100 terabits per second, which is orders of magnitude higher than the capacity of known fast optical switches. A fast-switching optical switch of such scalability significantly reduces network complexity and cost.

Abstract: Methods and apparatus for scheduling transfer of data bursts in a network comprising electronic edge nodes interconnected by bufferless core nodes are disclosed. Each edge node comprises a source node and a sink node, and each core node comprises several bufferless space switches operating in parallel. Each space switch has a master controller and one of the master controllers in a core node functions as a core-node controller. Each master controller has a burst scheduler for computing a schedule for transfer of data bursts, received from source nodes, to respective destination sink nodes. A core-node controller receives requests for bitrate allocations from source nodes and assigns each request to one of the master controllers of the core node. In one embodiment, a scheduler determines schedules for concatenated reconfiguration periods. In another embodiment, parallel schedulers determine schedules for overlapping reconfiguration periods.

Abstract: A high capacity distributed switching system comprises electronic edge nodes connected to a balanced bufferless switch which may be electronic or optical. The balanced bufferless switch comprises a balanced connector and a switch fabric. The balanced connector comprises an array of temporally cyclic rotator units having graduated rotation shifts and each having a prime number of output ports. The switch fabric may be a mesh interconnection of switch modules. Due to the use of the balanced connector, establishing a path through the switch fabric requires at most a second-order time-slot matching process for a high proportion of connection requests with a much reduced need for a third-order time-slot matching process required in a conventional mesh structure.

Abstract: Burst-switching nodes using a common-memory or a time shared space switch and employing flow-rate control are disclosed. Within a switching node, data bursts are segmented into data segments of a fixed size with some segments containing information bits as well as null bits. A switching node handles data streams allocated different flow rates and, for any data stream, the internal flow rate through the switching node can be higher than the external flow rate due to null padding of segmented data. The switching node is provided with a sufficient internal capacity expansion in order to offset the effect of null padding. A controller of the switching node is provided with a flow-rate-regulation apparatus to enable scheduling the transfer of data segments across the switching node in a manner that guarantees adherence to the allocated information flow rates.

Abstract: A future-proof network comprising multiple independent core media and universal edge nodes is disclosed. The edge nodes are equipped to evaluate the performance of each of the core media. Network-fabric decoupling and, more importantly protocol decoupling, permit graceful retirement of inferior core media and growth of superior core media.

Abstract: A circulating switch comprises switch modules of moderate capacities interconnected by a passive rotator. Data is sent from a one switch module to another switch module either directly, traversing the rotator once, or indirectly through at least one intermediate switch module where the rotator is traversed twice. A higher capacity extended circulating switch is constructed from higher-capacity switch modules, implemented as common memory switches and having multiple ports, interconnected through a multiplicity of rotators preferably arranged in complementary groups of rotators of opposite rotation directions. A polyphase circulating switch having a low switching delay is derived from a multi-rotator circulating switch by providing programmable rotators having adjustable relative rotator-cycle phases. A low delay high-capacity switch may also be constructed from prior-art medium-capacity rotator space switches with mutually phase-shifted rotation cycles.

Abstract: In a communication network comprising nodes and links between the nodes, a controller node disseminates routing information including nodal routing tables. A nodal routing table for a given node comprises alternate routes from the given node to other nodes in the network. A controller of the network receives traffic information from nodes and, based on the received traffic information, determines a set of adaptive routing information corresponding to each said node and transmits each set of adaptive routing information to the respective node. Determining the set of adaptive routing information is performed according to a courteous routing scheme. The routing scheme is labeled as “courteous” because, in a contention state, a node-pair that would suffer the least by directing a part of its traffic away from a preferred path yields to node pairs that suffer more by redirecting their traffic. Courteous routing increases the payload throughput and decreases real-time processing effort.

Abstract: A scheduling apparatus for a switch includes multiple schedulers which are assigned in a variety of ways to non-intersecting control domains for establishing connections through the switch. The control domains are defined by spatial and temporal aspects. The control domains may be dynamically selected and assigned to schedulers in a manner that achieves a high throughput gain. Control domains may be considered in a cyclic and/or a pipeline discipline for accommodating connection requests. The invention enables the realization of a highly scalable controller of a switching node of fine granularity that scales to capacities of the order of hundreds of terabits per second.

Abstract: A scheduling apparatus for a switch includes multiple schedulers which are assigned in a variety of ways to non-intersecting control domains for establishing connections through the switch. The control domains are defined by spatial and temporal aspects. The control domains may be dynamically selected and assigned to schedulers in a manner that achieves a high throughput gain. Control domains may be considered in a cyclic and/or a pipeline discipline for accommodating connection requests. The invention enables the realization of a highly scalable controller of a switching node of fine granularity that scales to capacities of the order of hundreds of terabits per second.

Abstract: A high capacity distributed switching system comprises electronic edge nodes connected to a balanced bufferless switch which may be electronic or optical. The balanced bufferless switch comprises a balanced connector and a switch fabric. The balanced connector comprises an array of temporally cyclic rotator units having graduated rotation shifts and each having a prime number of output ports. The switch fabric may be a mesh interconnection of switch modules. Due to the use of the balanced connector, establishing a path through the switch fabric requires at most a second-order time-slot matching process for a high proportion of connection requests with a much reduced need for a third-order time-slot matching process required in a conventional mesh structure.

Abstract: Burst-switching nodes using a common-memory or a time shared space switch and employing flow-rate control are disclosed. Within a switching node, data bursts are segmented into data segments of a fixed size with some segments containing information bits as well as null bits. A switching node handles data streams allocated different flow rates and, for any data stream, the internal flow rate through the switching node can be higher than the external flow rate due to null padding of segmented data. The switching node is provided with a sufficient internal capacity expansion in order to offset the effect of null padding. A controller of the switching node is provided with a flow-rate-regulation apparatus to enable scheduling the transfer of data segments across the switching node in a manner that guarantees adherence to the allocated information flow rates.

Abstract: A multi-grained high-performance rotorswitch scaling to high capacities is disclosed. In one embodiment, the rotorswitch comprises common-memory switch modules each of which cyclically accessing each other switch module for an access interval of a predefined value and transmitting, during the access interval, a number of data segments collectively having a duration not exceeding the access interval. The data segments transmitted to a given switch module during an access interval may be destined to several other switch modules. The switch modules may cyclically connect to each other using a plurality of rotators of the same rotational speed. In another embodiment, the rotorswitch uses rotators of different speeds connecting common-memory switch modules so that each of the switch modules has parallel cyclic access, possibly at different cyclic rates, to each other switch module.

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.