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 method in a physical network controller (130) for configuring physical resources to provide a physical layer connection in a communications network (100). The physical layer connection provides physical connectivity for a higher layer network connection controlled by a higher layer network controller (120) in a hierarchical arrangement with the physical network controller (130). The method comprising the physical network controller (130) receiving (210) an indication for a minimum traffic capacity for the physical layer connection. The physical network controller configuring (220) physical resources according to the received indication.

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 method (200) for managing a microwave network comprising a plurality of microwave nodes is disclosed, in which a microwave node is associated with a physical microwave path over which the microwave node is operable to transmit or receive a microwave signal, and in which a microwave path of at least some of the microwave nodes in the microwave network is reconfigurable. The method, performed at a domain controller of the microwave network, comprises exposing (210), on an interface of the domain controller, a link topology of the microwave network, wherein the link topology comprises, for a microwave node in the microwave network, a parameter quantifying the extent to which the microwave path associated with the microwave node is reconfigurable.

Abstract: Methods and apparatus are provided for locating a fault in an optical communication link. In one aspect, a method comprises determining a fault in a first optical link, and determining a fault in a second optical link. The method then determines that a first portion of the first optical link is co-located with a second portion of the second optical link and identifies, as a result of determining that the first portion is co-located with the second portion, that the fault in the first optical link is located in the first portion and/or the fault in the second optical link is located in the second portion.

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: Methods and apparatus are provided for locating a fault in an optical communication link. In one aspect, a method comprises determining a fault in a first optical link, and determining a fault in a second optical link. The method then determines that a first portion of the first optical link is co-located with a second portion of the second optical link and identifies, as a result of determining that the first portion is co-located with the second portion, that the fault in the first optical link is located in the first portion and/or the fault in the second optical link is located in the second portion.

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 (10) of bi-directional optical communication, the method comprising: generating (12) a first optical communication signal for transmission in one direction through an optical fibre, generating the first optical communication signal comprising: receiving information for transmission and generating (14) a baseband signal comprising a representation of the information; performing digital upconversion (16) of the baseband signal to form an upconverted baseband signal; performing optical modulation (18) of an optical carrier signal with the upconverted baseband signal; and restricting an optical spectrum of the first optical communication signal to a first portion of an optical channel frequency slot by performing one of digital filtering (16) in addition to digital upconversion and optical filtering (36) after optical modulation; and receiving (20) a second optical communication signal transmitted in an opposite direction through the optical fibre, the second optical communication signal having an optica

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 method (10) of bi-directional optical communication, the method comprising: generating (12) a first optical communication signal for transmission in one direction through an optical fibre, generating the first optical communication signal comprising: receiving information for transmission and generating (14) a baseband signal comprising a representation of the information; performing digital upconversion (16) of the baseband signal to form an upconverted baseband signal; performing optical modulation (18) of an optical carrier signal with the upconverted baseband signal; and restricting an optical spectrum of the first optical communication signal to a first portion of an optical channel frequency slot by performing one of digital filtering (16) in addition to digital upconversion and optical filtering (36) after optical modulation; and receiving (20) a second optical communication signal transmitted in an opposite direction through the optical fibre, the second optical communication signal having an optica

Abstract: A method in a physical network controller (130) for configuring physical resources to provide a physical layer connection in a communications network (100). The physical layer connection provides physical connectivity for a higher layer network connection controlled by a higher layer network controller (120) in a hierarchical arrangement with the physical network controller (130). The method comprising the physical network controller (130) receiving (210) an indication for a minimum traffic capacity for the physical layer connection. The physical network controller configuring (220) physical resources according to the received indication.

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.