US 10,256,935 B1Granted

Adaptive flexible grid in an optical network

AssigneeFujitsu Limited

InventorArvind Kumar

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Abstract

A disclosed method for optimizing channel selection in a flexible grid of an optical network may be used to select a minimum number of channels to allocate to traffic between pairs of optical transponders at a particular distance based on the modulation format and the FEC mechanism used. The method may include selecting an initial number of channels to allocate to the traffic, tuning the modulation format for the traffic while potentially reducing the number of channels, and tuning the FEC mechanism for the traffic while potentially further reducing the number of channels. The transponders may support multiple modulation formats of different orders and an adaptive FEC mechanism for which the maximum number of FEC overhead bytes is equal to the number of bytes in the transmitted data packets. The method may be implemented by an SDN controller and may be dependent on a feedback mechanism between the optical transponders.

Claims20

Dependent claims

A method for configuring a flexible grid in an optical network, comprising:

determining a first number of channels in the flexible grid to allocate to traffic between a transmitter in the optical network and a receiver in the optical network using a first modulation format selected for the traffic and including zero forward error correction (FEC) overhead bytes in packets transmitted between the transmitter and the receiver;
configuring the transmitter to allocate the first number of channels in the flexible grid to the traffic between the transmitter and the receiver and to transmit packets to the receiver using the first modulation format and zero FEC overhead bytes;
determining a second number of channels in the flexible grid to allocate to the traffic between the transmitter and the receiver, the second number of channels being less than the first number of channels, the determining including:
selecting a second modulation format for the traffic, the second modulation format being of a higher order than the first modulation format;
selecting a first non-zero number of FEC overhead bytes to be included in packets transmitted between the transmitter and the receiver;
and
determining a minimum number of channels for which transmission of packets between the transmitter and receiver using the second modulation format and the first non-zero number of FEC overhead bytes meets a predetermined performance measure;
and
re-configuring the transmitter to allocate the second number of channels in the flexible grid to the traffic between the transmitter and the receiver and to transmit packets to the receiver using the second modulation format and including the first non-zero number of FEC overhead bytes.

6 more elements

A system for implementing an adaptive flexible grid in a software-defined network (SDN) for optical transport, the system comprising:

a plurality of optical transponders;
and
an SDN controller, comprising a memory media and a processor having access to the memory media, wherein the memory media store instructions executable by the processor for:
determining a first number of channels in the flexible grid to allocate to traffic between a first transponder in the optical network and a second transponder in the optical network using a first modulation format selected for the traffic and including zero forward error correction (FEC) overhead bytes in packets transmitted between the first transponder and the second transponder;
configuring the first transponder to allocate the first number of channels in the flexible grid to the traffic between the first transponder and the second transponder and to transmit packets to the second transponder using the first modulation format and zero FEC overhead bytes;
determining a second number of channels in the flexible grid to allocate to the traffic between the first transponder and the second transponder, the second number of channels being less than the first number of channels, the determining including:
selecting a second modulation format for the traffic, the second modulation format being of a higher order than the first modulation format;
selecting a first non-zero number of FEC overhead bytes to be included in packets transmitted between the first transponder and the second transponder;
and
determining a minimum number of channels for which transmission of packets between the first transponder and the second transponder using the second modulation format and the first non-zero number of FEC overhead bytes meets a predetermined performance measure;
and
re-configuring the first transponder to allocate the second number of channels in the flexible grid to the traffic between the first transponder and the second transponder and to transmit packets to the second transponder using the second modulation format and including the first non-zero number of FEC overhead bytes.

9 more elements

An optical transponder, comprising:

first circuitry to support at least three modulation formats;
second circuitry to support the inclusion of any of a plurality of non-zero numbers of forward error correction (FEC) overhead bytes in packets transmitted by the optical transponder, including a maximum number of FEC overhead bytes equal to the number of data bytes in packets transmitted by the optical transponder;
third circuitry to transmit packets to another optical transponder over one or more channels in a flexible grid in an optical network;
fourth circuitry to:
receive first configuration information including:
information indicating a first number of channels in the flexible grid to allocate to traffic between the optical transponder and the other optical transponder;
information indicating a first modulation format with which packets are to be transmitted from the optical transponder to the other optical transponder;
and
information indicating that forward error correction is to be disabled for packets transmitted from the optical transponder to the other optical transponder;
and
receive second configuration information including:
information indicating a second number of channels in the flexible grid to allocate to traffic between the optical transponder and the other optical transponder, the second number of channels being less than the first number of channels;
information indicating a second modulation format with which packets are to be transmitted from the optical transponder to the other optical transponder, the second modulation format being of a higher order than the first modulation format;
and
information indicating that forward error correction is to be enabled and configured to include a first non-zero number of FEC overhead bytes in packets transmitted from the optical transponder to the other optical transponder;
and
fifth circuitry to:
configure the optical transponder to transmit packets to the other optical transponder in accordance with the first configuration information responsive to receipt of the first configuration information;
and
re-configure the optical transponder to transmit packets to the other optical transponder in accordance with the second configuration information responsive to receipt of the second configuration information.

17 more elements

Dependencies are inferred from the claim text.