Abstract: A method of transporting a client signal across an optical transport network (OTN) comprises dividing a received client signal into a plurality of parallel signals at a lower bit rate. The parallel signals are mapped into a respective number of optical data units (ODUs), each ODU having payload bytes and overhead bytes. Each ODU is mapped into a respective optical transport unit (OTUs) having payload bytes and overhead bytes. The OTUs are transmitted across respective optical carriers. Optical channel control information is inserted into the overhead bytes of the ODU and/or OTU. The optical channel control information is used to request a change in the optical carriers used to transport the client signal.

Abstract: A Layer 1 transport network, such as an Optical Transport Network (OTN), transports traffic in Layer 1 data transport units. Traffic received at a node of the transport network is mapped to Layer 1 data transport units according to destination such that each Layer 1 data transport unit carries traffic for a particular destination of the transport network. The Layer 1 transport network can carry a plurality of different traffic types and the node can map the received traffic to Layer 1 data transport units according to destination and traffic type. Identification information can be added to an overhead section associated with the Layer 1 data transport unit to indicate at least one of: traffic type and destination of the traffic carried within the data transport unit.

Abstract: A node for a communications network has a converter for digitizing at a receiver clock rate a received optical signal received over an optical link from an optical transmitter at a source node, a framer for detecting frames and a forward error correction part for correcting errors in the payload of the frame. An error rate in the received payload part is monitored and a processor sends, according to the monitored error rate, a request to the optical transmitter to adapt a length of the transmitted forward error correction part and to adapt a clock rate of the transmission of the frame if FEC length is reduced or FEC is disabled. This can enable power saving, when less FEC information is being sent.

Abstract: A method 10 of transmitting traffic in a communications network. The method comprises receiving client signal having a client bit rate and comprising traffic to be transmitted 12 and monitoring an indicator indicative of said client bit rate 12. The method further comprises setting a transmission bit rate at which to transmit the traffic 16. The transmission bit rate is set in dependence on said client bit rate. The method further comprises generating and transmitting a control signal arranged to cause a transmission apparatus to transmit the traffic at the transmission bit rate 18.

Abstract: A method of configuring a network element in a transport network comprising interrogating components of the network element about their characteristic and exchanging information on characteristics of the network element and its components with neighboring network elements. The network element is configured based on the exchanged information.

Abstract: A method of transporting a client signal across an optical transport network (OTN) comprises dividing a received client signal into a plurality of parallel signals at a lower bit rate. The parallel signals are mapped into a respective number of optical data units (ODUs), each ODU having payload bytes and overhead bytes. Each ODU is mapped into a respective optical transport unit (OTUs) having payload bytes and overhead bytes. The OTUs are transmitted across respective optical carriers. Optical channel control information is inserted into the overhead bytes of the ODU and/or OTU. The optical channel control information is used to request a change in the optical carriers used to transport the client signal.

Abstract: A node for a communications network has a converter for digitizing at a receiver clock rate a received optical signal received over an optical link from an optical transmitter at a source node, a framer for detecting frames and a forward error correction part for correcting errors in the payload of the frame. An error rate in the received payload part is monitored and a processor sends, according to the monitored error rate, a request to the optical transmitter to adapt a length of the transmitted forward error correction part and to adapt a clock rate of the transmission of the frame if FEC length is reduced or FEC is disabled. This can enable power saving, when less FEC information is being sent.

Abstract: A method of transporting a client signal across an optical transport network (OTN) comprises dividing a received client signal into a plurality of parallel signals at a lower bit rate. The parallel signals are mapped into a respective number of optical data units (ODUs), each ODU having payload bytes and overhead bytes. Each ODU is mapped into a respective optical transport unit (OTUs) having payload bytes and overhead bytes. The OTUs are transmitted across respective optical carriers of a super-channel, the optical carriers of the super-channel being synchronously modulated. Optical channel control information is inserted into the overhead bytes of the ODU and/or OTU. The optical channel control information is used to manage and/or control the transport of the client signal using the super-channel.

Abstract: A node for a communications network has a converter for digitizing at a receiver clock rate a received optical signal received over an optical link from an optical transmitter at a source node, a framer for detecting frames and a forward error correction part for correcting errors in the payload of the frame. An error rate in the received payload part is monitored and a processor sends, according to the monitored error rate, a request to the optical transmitter to adapt a length of the transmitted forward error correction part and to adapt a clock rate of the transmission of the frame if FEC length is reduced or FEC is disabled. This can enable power saving, when less FEC information is being sent.

Abstract: A method of configuring a network element in a transport network comprising interrogating components of the network element about their characteristic and exchanging information on characteristics of the network element and its components with neighbouring network elements. The network element is configured based on the exchanged information.

Abstract: A method of transporting a client signal across an optical transport network (OTN) comprises dividing a received client signal into a plurality of parallel signals at a lower bit rate. The parallel signals are mapped into a respective number of optical data unit (ODUs), each ODU having payload bytes and overhead bytes. Each ODU is mapped into a respective optical transport unit (OTUs) having payload bytes and overhead bytes. The OTUs are transmitted across respective optical carriers of a super-channel, the optical carriers of the super-channel being synchronously modulated. Optical channel control information is inserted into the overhead bytes of the ODU and/or OTU. The optical channel control information is used to manage and/or control the transport of the client signal using the super-channel.

Abstract: A node for a communications network has a converter for digitizing at a receiver clock rate a received optical signal received over an optical link from an optical transmitter at a source node, a framer for detecting frames and a forward error correction part for correcting errors in the payload of the frame. An error rate in the received payload part is monitored and a processor sends, according to the monitored error rate, a request to the optical transmitter to adapt a length of the transmitted forward error correction part and to adapt a clock rate of the transmission of the frame if FEC length is reduced or FEC is disabled. This can enable power saving, when less FEC information is being sent.

Abstract: A Layer 1 transport network, such as an Optical Transport Network (OTN), transports traffic in Layer 1 data transport units. Traffic received at a node of the transport network is mapped to Layer 1 data transport units according to destination such that each Layer 1 data transport unit carries traffic for a particular destination of the transport network. The Layer 1 transport network can carry a plurality of different traffic types and the node can map the received traffic to Layer 1 data transport units according to destination and traffic type. Identification information can be added to an overhead section associated with the Layer 1 data transport unit to indicate at least one of: traffic type and destination of the traffic carried within the data transport unit.

Abstract: A method 10 of transmitting traffic in a communications network. The method comprises receiving client signal having a client bit rate and comprising traffic to be transmitted 12 and monitoring an indicator indicative of said client bit rate 12. The method further comprises setting a transmission bit rate at which to transmit the traffic 16. The transmission bit rate is set in dependence on said client bit rate. The method further comprises generating and transmitting a control signal arranged to cause a transmission apparatus to transmit the traffic at the transmission bit rate 18.

Abstract: A transmission method in which a first signal frame, carrying a payload in a first part of the signal frame and second information in a second part of the signal frame, is transmitted intact between a signal source and a signal destination by copying the second information into the first part of at least one additional signal frame, transmitting both frames between the signal source and the signal destination and, at the destination, reconstructing the first signal frame by retrieving its original second information from the first part or parts of the additional signal frame or frames and placing the retrieved second information in the second part of the first signal frame. A typical application of the transmission method lies in its use in an SDH transmission system.

Abstract: A transmission method in which a first signal frame, carrying a payload in a first part of the signal frame and second information in a second part of the signal frame, is transmitted intact between a signal source and a signal destination by copying the second information into the first part of at least one additional signal frame, transmitting both frames between the signal source and the signal destination and, at the destination, reconstructing the first signal frame by retrieving its original second information from the first part or parts of the additional signal frame or frames and placing the retrieved second information in the second part of the first signal frame. A typical application of the transmission method lies in its use in an SDH transmission system.

Abstract: Channels are groomed in a wavelength division multiplexed (WDM) communication system having a plurality of system nodes interconnected together by a ring formation of optical fiber waveguides for guiding communication traffic bearing radiation between the nodes. The radiation comprises a plurality of wavelength channels for conveying communication traffic. The channels are spaced over a channel wavelength spectrum. The wavelength channels being used within the system are selected to convey communication traffic (active channels) such as to consolidate them into a relatively more compact part or parts of the wavelength spectrum such as to occupy less communication bandwidth.