Telefonaktiebolaget Lm Ericsson (publ)

Stmicroelectronics S.r.l.

Ericsson Ab

The Royal Institution for the Advancement of Learning/mcgill University

Scuola Superiore Di Studi Universitari E Di Perfezionamento Sant'anna

Scuola Superiore Santanna

Piero Castoldi

Filippo Cugini

Nicola Sambo

Giulio Bottari

Paola Iovanna

Nicola Andriolli

Antonella Bogoni

Pier Giorgio Raponi

Francesco Paolucci

Luca Poti

Mirco Scaffardi

Isabella Cerutti

Annikki Welin

Alberto Bianchi

Luca Valcarenghi

Alessio Giorgetti

Roberto Magri

Gianmarco Bruno

Antonio D'Errico

Marzio Puleri

Giuseppe Avellone

Hisashi Kobayashi

Luca Fanucci

Gianluca Berrettini

Odile Liboiron-Ladouceur

Claudio Porzi

Andrea Concil

Md Shafiqul Hai

Lorena Simoni

Andrea Sgambelluri

Gianluca Berettini

Matteo Dallaglio

Riccardo Grasso

A method for managing a telecommunication network comprising the steps of identification, by the central controller, of an updated condition of availability of resources of the network, and association of a plurality of updated sequences of instructions, comparison of the plurality of updated sequences of instructions with a plurality of not updated sequences of instructions associated with the last condition of availability. In case that the plurality of updated sequences of instructions is different from the plurality of not updated sequences of instructions, a step is provided of sending an updated sequence of instructions to each nodal device, on the basis of the service class of the data traffic of the device. A step is furthermore provided of checking, by the local controller, a condition of service of the data traffic at time ranges &#x3b4;, said updated sequence of instructions associating to each condition of service an optimal working status to be attributed to the data traffic. A step is then provided of comparison of the condition of service with an optimal condition of service and, in case that the condition of service is different, a step is provided of starting, by the local controller, the updated sequence of instructions for changing a status of the data traffic. It is further provided a step of sending to the central controller data concerning the change of the working status.

Method for managing a telecommunication network

An optical switch () comprising: inputs () to receive input optical signals at respective wavelengths and having planar wavefronts; conversion apparatus () to convert each input optical signal into a respective optical signal having a respective helical wavefront, each helical wavefront having a different orbital angular momentum, OAM; optical multiplexing apparatus () to receive each helical wavefront optical signal from the conversion apparatus and to multiplex the helical wavefront optical signals into an OAM multiplexed optical signal; and optical demultiplexing apparatus () comprising a plurality of outputs (), the optical demultiplexing apparatus arranged to: receive the OAM multiplexed optical signal; demultiplex the OAM multiplexed optical signal into a plurality of wavelength multiplexed optical signals each having a different OAM; reconvert each wavelength multiplexed optical signal from its helical wavefront into a respective planar wavefront; and deliver each planar wavefront wavelength multiplexed optical signal to a respective one of the outputs according to the respective OAM it had before reconversion.

Optical switching

An optical carrier selector system is provided for selecting a wanted carrier signal from a multi-carrier signal comprising a plurality of carrier signals. The optical carrier selector system comprises a series of optical filter devices. Each optical filter device of the series comprises an input port for receiving a signal comprising two or more carrier signals, each optical filter device being configured to filter out an unwanted carrier signal. Each optical filter device also comprises an output port for outputting at least the wanted carrier signal and any remaining signals that have not been filtered out by that particular optical filter device, and a drop port for outputting the unwanted carrier signal that is being filtered out by the respective optical filter device. By outputting from a drop port the unwanted carrier signal that is being filtered out by the respective optical filter device, this has the advantage of enabling the operation of the optical carrier selector system to be monitored for proper operation, and controlled or adjusted if necessary.

Optical carrier selector system and method

Slots () for transmission of data of a particular transmission type over an optical network are allocated by selecting a first available slot (_) at an ordinal position corresponding to a multiple of n and allocating the selected first available slot and the next n&#x2212;1 consecutive slots (__) from the selected first available slot (_), if all n&#x2212;1 consecutive slots (__) are available, for transmission of data of the particular transmission type. The data is transmitted over an optical network comprising a plurality of nodes () interconnected by optical sections () the nodes () supporting a plurality of transmission types, wherein transmission of data of the particular transmission type requires a predetermined number n of consecutive slots. Alternatively the slots may be divided in groups () and slots are allocated to a group in which all slots are available.

Method and apparatus for allocating slots for transmission of data

Traffic recovery is supported at a switching node () of an OpenFlow network (). The switching node () has a flow table () for storing flow entries () which determine forwarding of received packets between the ports. A switching node () installs () a flow entry for a back up path in the flow table (). The switching node () renews () the flow entry for the backup path based on at least one of: (i) an association between the flow entry for the backup path and a flow entry for a working path at the switching node, wherein the flow entry for the backup path is renewed when the flow entry for the working path is used to forward a received packet; (ii) receiving a flow entry renewal packet from another switching node on the backup path. A backup path can be configured for each of multiple points of failure in the working path.

Traffic recovery in openflow networks

A method of changing the spectral position of a lightpath between a source node and a destination node of an optical network. The optical network uses a flexible grid for spectral allocation and the lightpath has been allocated first spectral resources at a first spectral position. The method comprises, at the source node, reserving additional spectral resources for the lightpath which are contiguous in frequency with the first spectral resources. The method comprises re-tuning a light source at the source node such that the lightpath moves in frequency from using the first spectral resources at the first spectral position to using second spectral resources at a second spectral position, wherein the second spectral resources comprise at least some of the additional spectral resources. The method comprises releasing at least some of the first spectral resources. The source node continues to send traffic over the lightpath during the re-tuning.

Changing the spectral position of a lightpath

Scalability and energy efficiency are key issues in data centers imposing tight constraints on the networking infrastructure connecting the servers. Optical interconnection mitigates electronic limitations but the additional flexibility offered by WDM and datarate across a data center interconnection network requires architectural design, photonic technologies, and operating strategies be selected and optimized to meet power consumption requirements. Multi-plane architectures based upon space-wavelength domain architectures have been proposed to overcome scalability limitations. It would be beneficial to extend space and time switching domains with the wavelength domain for additional capacity to increase throughput as well as providing same electro-optic interface. Accordingly, the inventors have established space-time domain interconnection network architectures with wavelength domain overlay overcoming power consumption issues, especially at low utilization, by exploiting all-optical implementations with active elements which act simultaneously as a switch and an amplifier, and the possibility to remain in an idle state when unused.

Methods and devices for space-time multi-plane optical networks

A path computation client (PCC) can request a path computation element (PCE) to compute a path across a wavelength switched optical network. PCC sends a request which identifies end nodes. The end nodes can support a plurality of possible values of a transmission parameter, such as modulation format or Forward Error Correction (FEC) type. The PCE computes a path between the end nodes and sends a reply to the PCC. The reply identifies the path between the end nodes and identifies a selected value of the transmission parameter for the computed path. The reply can comprise a spectrum assignment for the path. The reply can be a PCE Communication Protocol (PCEP) Reply message.

Path computation in wavelength switched optical networks

In an optical communications network using bandwidth variable wavelength switching, routing and spectrum assignment for a traffic request for x sub-carriers of a super-channel, involves checking for an existing super-channel having sufficient potential sub-carriers not currently active. If not found, then possible paths for a new super-channel are identified and a path is selected and sub-carriers assigned. By trying first to use inactive potential sub-carriers of an existing super-channel, fewer super channels overall are needed, and thus fewer super transponders are needed. This can reduce blocking probabilities and can reduce capital costs. The search for possible paths can try to avoid or reduce overlap with spectrum of existing super channels, or compare possible paths by weighting according to amounts of overlap.

Routing for super channel for bandwidth variable wavelength switched optical network

Routing and bandwidth assignment of new paths of different bandwidths, occupying different numbers of adjacent frequency slots in a wavelength switched optical network, involves selecting a route, and assigning a set of adjacent frequency slots. The assignment can place wider bandwidth ones of the new paths at an opposite end of a spectrum of the available frequency slots, to an end where narrower bandwidth ones are placed. A size of sets of available adjacent slots remaining after the assignment is likely to be increased, compared to a conventional first fit assignment. A wider subsequent new path can sometimes be accommodated along all or some of the route and thus the blocking probability can be lowered. The selecting of which of the possible routes to use can be made dependent on which has more sets of available adjacent frequency slots, or which has a wider gap between occupied slots.

Routing and bandwidth assignment for flexible grid wavelength switched optical networks

A method of configuring an optical path, comprising: selecting a path from a first to a second node in an optical communications network; identifying each wavelength that may be used continuously across the path and selecting a transmission wavelength for the optical path one of the identified wavelengths for which: a fixed wavelength direction-bound add/drop transponder add operable at said wavelength is available at each node; if that first requirement is not met, a fixed wavelength direction-bound add/drop transponder or a fixed wavelength directionless add/drop transponder operable at said wavelength is available at each node; and if that second requirement is not met, a tunable wavelength direction-bound add/drop transponder or a tunable wavelength directionless add/drop transponder operable at said wavelength is available at each node.

Method of configuring an optical path, a path computation engine and an optical communications network node

An optical transmission network comprises nodes which support a plurality of different wavelength channels and support at least a first bitrate traffic type and the second bitrate traffic type on respective wavelength channels. A connection of the second bitrate traffic type is established on an available wavelength, if the wavelength offers an acceptable quality of transmission using a first quality of transmission calculation. Alternatively, a connection of the second bitrate traffic type is established on a wavelength which is spaced, by a guard band, from wavelengths used for connections of the first bitrate traffic type, if the wavelength offers an acceptable quality of transmission using a second quality of transmission calculation. The second quality of transmission calculation is less stringent than the first quality of transmission calculation, and can ignore the effects of interference due to cross-phase modulation. The guard band is a wavelength spacing at which the interference between a connection of the first bitrate traffic type and a connection of the second bitrate traffic type is less than a predetermined amount.

Establishing connections in a multi-rate optical network

A method of allocating a wavelength to a lightpath in a wavelength multiplex for use in an optical network comprising nodes connected by optical links, wherein the wavelength multiplex is adapted to support lightpaths of two different bitrates. The disclosed method allows for efficient allocation of wavelengths that prevents wasting bandwidth and mitigates detrimental effects of cross-phase modulation.

Method and apparatus for dynamic wavelength allocation in wavelength switched optical networks

A method () of configuring a synchronous optical switch to route received data cells. The synchronous optical switch comprises optical switch transmitter modules, each comprising tunable optical transmitters, optical switch receiver modules, each comprising optical receivers, and optical connections between the transmitter modules and receiver modules. For each optical switch transmitter module, the method: assigns () wavelengths associated with the received data cells to the transmitters such that each wavelength is assigned to a different transmitter; and generates () a control signal for controlling the operating wavelength of each transmitter. For each wavelength, the method: allocates () to each transmitter an optical connection such that each optical switch transmitter module has no more than one connection exiting it at said wavelength and each optical receiver module has no more than one connection entering it at said wavelength; and generates () a control signal for connecting each transmitter to the respective optical connection.

Configuring synchronous optical switches

A node () for a multi-token optical communications network has optical channels between the node and other nodes, each channel having a token (T, T, T), passed between nodes, to indicate that a corresponding optical channel is available for transmission during a token holding time. The node has a transmitter () for transmitting packets over the optical channels, a buffer () for queuing packets before transmission, and a transmit controller () configured to control the buffer to forward an initial packet or packets from the buffer to the transmitter once a token has been received. The transmit controller determines how much of the token holding time remains after the transmission of the initial packet or packets, and then controls the buffer to forward a further packet according to the remaining token holding time. A maximum packet delay can be reduced where there is asymmetric traffic. A token holding time can be different for different nodes.

Growing community of inventors

Pisa, Italy

Piero Castoldi