Telefonaktiebolaget Lm Ericsson (publ)

The Royal Institution for the Advancement of Learning/mcgill University

Scuola Superiore Santanna

Pier Giorgio Raponi

Piero Castoldi

Nicola Andriolli

Alberto Bianchi

Antonella Bogoni

Luca Poti

Marzio Puleri

Odile Liboiron-Ladouceur

Isabella Cerutti

Md Shafiqul Hai

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 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.

Control of token holding in multi-token optical network

A synchronous packet switch comprises output modules, input modules, optical connections and a switch control unit. The output modules comprise optical receivers each configured to receive optical signals at a different wavelength. The input modules receive electric signals carrying data cells to be routed. Each input module comprises optical transmitters, each configurable to generate an optical signal at a different wavelength, and routing apparatus comprising output ports. Each output module has at least one output port allocated to it. The routing apparatus is configurable to route a received optical signal to a selected output port. The optical connections are arranged to couple output ports to respective output modules. The switch control unit controls routing of the optical signals from the transmitters to the output modules and generates a routing control signal for configuring the routing apparatus to route an optical signal from a transmitter to a selected output port.

Synchronous packet switches

Growing community of inventors

Pisa, Italy

Pier Giorgio Raponi