Abstract: A method (100) of end-to-end path computation across a plurality of domains (20) in a communication network comprises receiving (101) a request for a path across the plurality of domains. The method comprises computing (110) in a network control entity (50) the end-to-end path across the plurality of domains as part of a hierarchical path computation. Computing the end-to-end path comprises determining if a stored path corresponding to at least a part of the end-to-end path matches one or more criteria of the end-to-end path, and if so, using the stored path for the end-to-end path computation. The method further comprises transmitting (120) information indicating at least part of the stored path to a domain control entity (30) configured to control a said one of the plurality of domains involved in the end-to-end path.

Abstract: Apparatus and methods are provided for path computation for a service in a telecommunications network. In one aspect, a method comprises receiving a request to schedule the service utilizing the network in a time period determining that a path for the service is not available for the whole of the time period, and determining a plurality of paths for the service, each of the plurality of paths being available during a respective portion of the time period, such that at least one of the plurality of paths is available for the service at any time during the time period.

Abstract: Apparatus and methods are provided for scheduling services in a traffic-engineered communications network. In one aspect a method comprises: receiving a request to schedule a second service utilizing the network in a second time period, wherein the second time period overlaps a first time period in which a first service utilizing the network has already been scheduled; and computing a path for the second service through the network. The step of computing the path for the second service through the network comprises: responsive to a determination that the request is received less than the threshold period of time before the start of the first time period, disallowing the second service from pre-empting the first service.

Abstract: A path computation method involves receiving (200) a request for computation of a new path in the network, the request indicating a future time interval when the path is desired. Subsequently a future network status is generated (210, 212, 214), having a representation of availability of path resources at the future time interval, based on selected paths already reserved at that future time interval. Then there is a step of computing (220) which of the path resources to select for the new path according to the future network status. By generating this future network status when the future time interval is known, it can be generated in respect of a limited time interval rather than covering all possible future reservable times. Thus the benefits of time aware path computation can be achieved without the need for maintaining a huge database of availability at all future times, of all the path resources.

Abstract: Apparatus and methods are provided for scheduling services in a traffic-engineered communications network. In one aspect a method comprises: receiving a request to schedule a second service utilizing the network in a second time period, wherein the second time period overlaps a first time period in which a first service utilizing the network has already been scheduled; and computing a path for the second service through the network. The step of computing the path for the second service through the network comprises: responsive to a determination that the request is received less than the threshold period of time before the start of the first time period, disallowing the second service from pre-empting the first service.

Abstract: A path computation method for use by a control entity (20) of a tenant (11) in a multi-tenant communications network (40) receives a request for computation of a path in the communications network (40) and obtains a current virtual topology of the communications network from a shared topology store (31) which is shared by the tenants. The virtual topology is a topology of the communications network which is available for use by the tenant (11). The virtual topology is used to service the request. The method may create the path. The path computation may be in respect of a future time interval.

Abstract: A method of path computation in a segment routing network, the network comprising a set of nodes. The method comprises receiving a request for computation of a path between end nodes in the network, the request including a constraint. The method further comprises determining a segment identifier-optimised path defined by a stack of one or more segment identifiers, wherein the segment identifier-optimised path meets the constraint. The determining of the segment identifier-optimised path comprises analyzing a topology of the network comprising: at least a sub-set of the nodes, links between adjacent nodes indicative of possible paths between the nodes, and virtual links between pairs of nodes indicative of possible paths between the pairs of nodes. The method further comprises outputting at least one segment identifier which defines the determined path.

Abstract: A radio over fibre system (5) comprises a base station (10, 20) with a first base station node (10) and a second base station node (20) connected by an optical communication link (30). At least one of the base station nodes (10, 20) comprises an optical transmitter (17, 23). A method of determining an operating parameter for the optical transmitter (17, 23) comprises receiving signal quality parameters for a plurality of user equipments (UE) served by the base station (10, 20). The method determines an operating parameter of the optical transmitter using the determined signal quality parameters of the plurality of user equipments (UE). The operating parameter of the optical transmitter can be a modulation parameter.

Abstract: Apparatus and methods are provided for path computation for a service in a telecommunications network. In one aspect, a method comprises receiving a request to schedule the service utilizing the network in a time period determining that a path for the service is not available for the whole of the time period, and determining a plurality of paths for the service, each of the plurality of paths being available during a respective portion of the time period, such that at least one of the plurality of paths is available for the service at any time during the time period.

Abstract: A path computation method involves receiving (200) a request fir computation of a new path in the network, the request indicating a future time interval when the path is desired. Subsequently a future network status is generated (210, 212, 214), having a representation of availability of path resources at the future time interval, based on selected paths already reserved at that future time interval. Then there is a step of computing (220) which of the path resources to select for the new path according to the future network status. By generating this future network status when the time interval is known, it can be generated in respect of a limited time interval rather than covering all possible future reservable times. Thus the benefits of time aware path computation can be achieved without the need for maintaining a huge database of availability at all future times, of all the path resources.

Abstract: A method (100) of end-to-end path computation across a plurality of domains (20) in a communication network comprises receiving (101) a request for a path across the plurality of domains. The method comprises computing (110) in a network control entity (50) the end-to-end path across the plurality of domains as part of a hierarchical path computation. Computing the end-to-end path comprises determining if a stored path corresponding to at least a part of the end-to-end path matches one or more criteria of the end-to-end path, and if so, using the stored path for the end-to-end path computation. The method further comprises transmitting (120) information indicating at least part of the stored path to a domain control entity (30) configured to control a said one of the plurality of domains involved in the end-to-end path.

Abstract: A path computation method involves receiving (200) a request for computation of a new path in the network, the request indicating a future time interval when the path is desired. Subsequently a future network status is generated (210, 212, 214), having a representation of availability of path resources at the future time interval, based on selected paths already reserved at that future time interval. Then there is a step of computing (220) which of the path resources to select for the new path according to the future network status. By generating this future network status when the future time interval is known, it can be generated in respect of a limited time interval rather than covering all possible future reservable times. Thus the benefits of time aware path computation can be achieved without the need for maintaining a huge database of availability at all future times, of all the path resources.

Abstract: A path computation method for use by a control entity (20) of a tenant (11) in a multi-tenant communications network (40) receives a request for computation of a path in the communications network (40) and obtains a current virtual topology of the communications network from a shared topology store (31) which is shared by the tenants. The virtual topology is a topology of the communications network which is available for use by the tenant (11). The virtual topology is used to service the request. The method may create the path. The path computation may be in respect of a future time interval.

Abstract: A radio over fibre system (5) comprises a base station (10, 20) with a first base station node (10) and a second base station node (20) connected by an optical communication link (30). At least one of the base station nodes (10, 20) comprises an optical transmitter (17, 23). A method of determining an operating parameter for the optical transmitter (17, 23) comprises receiving signal quality parameters for a plurality of user equipments (UE) served by the base station (10, 20). The method determines an operating parameter of the optical transmitter using the determined signal quality parameters of the plurality of user equipments (UE). The operating parameter of the optical transmitter can be a modulation parameter.

Abstract: A path computation method involves receiving (200) a request for computation of a new path in the network, the request indicating a future time interval when the path is desired. Subsequently a future network status is generated (210, 212, 214), having a representation of availability of path resources at the future time interval, based on selected paths already reserved at that future time interval. Then there is a step of computing (220) which of the path resources to select for the new path according to the future network status. By generating this future network status when the future time interval is known, it can be generated in respect of a limited time interval rather than covering all possible future reservable times. Thus the benefits of time aware path computation can be achieved without the need for maintaining a huge database of availability at all future times, of all the path resources.

Abstract: A method of path computation in a segment routing network, the network comprising a set of nodes. The method comprises receiving a request for computation of a path between end nodes in the network, the request including a constraint. The method further comprises determining a segment identifier-optimised path defined by a stack of one or more segment identifiers, wherein the segment identifier-optimised path meets the constraint. The determining of the segment identifier-optimised path comprises analyzing a topology of the network comprising: at least a sub-set of the nodes, links between adjacent nodes indicative of possible paths between the nodes, and virtual links between pairs of nodes indicative of possible paths between the pairs of nodes. The method further comprises outputting at least one segment identifier which defines the determined path.

Abstract: A method of optimizing optical signal quality in an optical communications link comprising a plurality of sections each comprising an optical amplification apparatus and an optical fiber span, the method comprising: for each section, determining a respective optimal optical channel power which minimizes a sum of an indication of a respective linear optical noise and an indication of a respective nonlinear optical noise; and generating and transmitting at least one control signal arranged to cause a target optical channel power of each section to be set to the respective optimal optical channel power.

Abstract: A method includes: selecting an optical pump signal power of a Raman amplifier such that a saturated gain of the Raman amplifier is at a maximum operating level without exceeding a gain threshold above which an optical signal to noise ratio penalty is no longer negligible in the Raman amplifier; selecting an optical signal power for at least one optical communication signal to be transmitted across the optical link to maximise a Q-factor of the optical signal when the Raman amplifier is configured for said maximum operating level of the saturated gain; generating a pump signal power control signal to cause an optical pump signal source of the Raman amplifier to generate an optical pump signal having the selected optical pump signal power; and generating a signal power control signal configured to cause the optical communication signal to be delivered into the optical link at the selected optical signal power.

Abstract: A method includes: selecting an optical pump signal power of a Raman amplifier such that a saturated gain of the Raman amplifier is at a maximum operating level without exceeding a gain threshold above which an optical signal to noise ratio penalty is no longer negligible in the Raman amplifier; selecting an optical signal power for at least one optical communication signal to be transmitted across the optical link to maximise a Q-factor of the optical signal when the Raman amplifier is configured for said maximum operating level of the saturated gain; generating a pump signal power control signal to cause an optical pump signal source of the Raman amplifier to generate an optical pump signal having the selected optical pump signal power; and generating a signal power control signal configured to cause the optical communication signal to be delivered into the optical link at the selected optical signal power.

Abstract: A method of optimizing optical signal quality in an optical communications link comprising a plurality of sections each comprising an optical amplification apparatus and an optical fibre span, the method comprising: for each section, determining a respective optimal optical channel power which minimizes a sum of an indication of a respective linear optical noise and an indication of a respective nonlinear optical noise; and generating and transmitting at least one control signal arranged to cause a target optical channel power of each section to be set to the respective optimal optical channel power.