Abstract: Methods for automatically discovering links between a first node of a first operating domain and a second node of a second operating domain of a communication network are disclosed. The methods may be implemented at the first node, the second node, or a control node. The first and second nodes communicate in-band control messages. These messages are encoded using a size of the packets of the control messages, and provide information about the first node and a first interface used by the first node for sending the control messages. The first and second nodes also communicate link messages with the control node. The link messages comprise information received in the in-band control messages and information about a second interface used by the second node for receiving the in-band control messages.

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: It is disclosed a coordinator (22), a physical network controller (24, 26) and methods therein for enabling end-point mobility of a traffic engineering, TE, tunnel in a multi-domain network. Based on a request for virtual network configuration of one or both of the ingress and the egress end-points of the TE tunnel, the coordinator of a multi-domain network determines 54, S416 a second request for virtualizing said one or both of the ingress and the egress end-points of the TE tunnel. The physical network controller may then virtualize end-points of the TE tunnel, providing a virtualized end-point, VEP, TE tunnel, having end-point mobility capacity. Recovery mechanisms of tunnel paths may be efficiently implemented. The present disclosure also provides scalability improvements and operational expenditure, OPEX, savings, as compared to state of art TE tunnels.

Abstract: A converged Operations Support System (OSS) for managing a hierarchical network environment including a plurality of network domains. In one embodiment, each OSS component of the OSS is mapped against a particular hierarchical information layer of a plurality of hierarchical information layers required to manage the hierarchical network environment. When a query is received at a northbound interface of the OSS from an external requester, a determination is made as to which particular hierarchical information layers are required to generate a response to the query. Responsive to the determination, the query may be forwarded to one or more OSS components mapped to the particular hierarchical information layers for generating a response.

Abstract: Methods for segment routing in a software-defined networking (SDN) system are disclosed. In one embodiment, a method includes receiving a plurality of values of maximum segment identifier (SID) depths, each from one network element of the SDN system, and identifying a path for a packet to transmit through a plurality of network elements, where a plurality of SIDs corresponding to the plurality of network elements is ordered to represent the path. The method further includes splitting the path into a plurality of sub-paths based on the values of the maximum SID depths of the plurality of network elements, where each network element, for the path, is allocated to process a number of ordered SIDs, and where the number is within the network element's maximum SID depth, and causing packet forwarding of the packet along the plurality of sub-paths based on SIDs allocated to the network elements.

Abstract: An in band control channel is created between nodes of a communication network in which the nodes have limited capability of inspecting the payload of packets to be transported over the network. The in band control channel is created by transmitting a plurality of dummy packets, each dummy packet having one of a plurality of different predetermined lengths, the sequence of dummy packets defining a code corresponding to at least one control command.

Abstract: A connection-oriented network has a working path and a segment recovery path for a segment of the working path. The working path has a branch node at an end of the segment where the segment recovery path connects to the working path. The branch node is not located at an end node of the working path. Control plane signalling is received at an end node of the working path from a node along the working path, indicating that a failure has occurred along the working path. The end node determines, from the received control plane signalling, if the failure has occurred outside the segment of the working path. When it is determined that the failure has occurred outside the segment of the working path, a notification is sent to the branch node. The notification is an instruction not to reroute to the segment recovery path.

Abstract: The present disclosure generally relates to the support of optical connection setup. More specifically, the present disclosure relates to a technique of supporting provision of a connection via a data communication network of an optical network between packet network islands. A method embodiment comprises establishing a Border Gateway Protocol-Link State, BGP-LS, connection via the DCN between a first edge node of the first packet network island and a BGP-LS node in the optical network.

Abstract: Distributed management of analytics tasks in a programmable network (100) having a controller (SDNC, 10, 11), a plurality of network nodes (20, N1-N5) coupled to the controller by a Data Communications Network DCN, and a plurality of analytics servers (30) each coupled to a network node, involves the controller selecting which of the analytics servers to use for an analytics task. The selection is based on how data logged by respective ones of the network nodes and needed for that analytics task, can be routed to the analytics servers. The controller sends to the selected analytics server, an indication of the analytics task and an indication of what data logged by the network nodes is to be used in the analytics task.

Abstract: A method of provisioning a control plane in a multi-technology network in response to a first connection request received from a client. The method comprises receiving the first connection request at a control plane dispatcher; analysing said first connection request and selecting a control plane based on results of the analysis and characteristics of control planes at the disposal of the dispatcher in the multi-technology network. The control plane dispatcher selects on a per connection request basis what is the best technology for that request and its requirements, taking also into account the status of the network resources.

Abstract: A method and a network node for managing allocation of network resources in restoration of traffic in a connection oriented network are disclosed. The method comprises restoring a first traffic from a first path on an alternative path if the first path is affected by a first failure and assigning a reserved status to resources of the first path no longer used for carrying the first traffic. If a second path is affected by a second failure the method comprises restoring a second traffic from the second path, wherein the restoration of the second traffic does not use the resources having the reserved status.

Abstract: A method of providing state synchronization between a controller and a switch in a communications network, wherein the controller provides flow data for routing flows through the switch and transmits, in flow modification messages, the flow data to the switch for storage in flow tables, the state synchronization comprising ensuring that flow data in the flow tables of the switch are consistent with the flow data provided by the controller. The method comprises, by the controller (19), providing (21) an identifier in each flow modification message.

Abstract: A method of local path protection in a node on a shared alternative path of a network. The method comprising receiving a signal switched on a primary label switched path (LSP). The signal is switched by lambda-switching or time-division multiplex TDM switching. The method further comprises receiving identification information arranged to identify the signal, and forwarding the signal on the alternative path based on the identification information.

Abstract: A method and a network node for managing allocation of network resources in restoration of traffic in a connection oriented network are disclosed. The method comprises restoring a first traffic from a first path on an alternative path if the first path is affected by a first failure and assigning a reserved status to resources of the first path no longer used for carrying the first traffic. If a second path is affected by a second failure the method comprises restoring a second traffic from the second path, wherein the restoration of the second traffic does not use the resources having the reserved status.

Abstract: A connection-oriented network has a first working path (W1) and a second working path (W2). A node (E) receives signalling to allocate resources for a part of a recovery path (R1) for the first working path (W1). The resources are shared by the recovery path (R1) for the first working path and a recovery path (R2a) for the second working path (W2). The node (E) stores an association between the shared resources and a node (A) on the first working path, identified in the signalling, which should be notified when the shared resources are used by the recovery path (R2a) for the second working path (W2). An RSVP-TE <NOTIFY_REQUEST> object in the signalling carries an address of the node to be notified. The node (E) sends an RSVP-TE Notify message to a node (A) on the first working path (W1) which indicates that the shared resources are in use.

Abstract: Aspects provide a method (10, 100, 150, 160) of controlling a multi-layer communication network comprising a client network and a server network. The method comprises obtaining (12;164) from the server network at least one path characteristic for a path in the server network between server network nodes; and providing (14, 152, 166) to the client network an indication of the at least one path characteristic of the server network.

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 network architecture is provided for enabling end-to-end paths to be computed across a plurality of network domains. The network architecture comprises a plurality of child path computation elements associated with a plurality of respective network domains, each child path computation element adapted to compute a path segment within its respective network domain. A parent path computation element adapted to compute an end-to-end path across a plurality of network domains in conjunction with the plurality of respective child path computation elements.

Abstract: A method in a controller node for performing segment routing in a non-packet data network comprising a plurality of nodes, comprises receiving information relating to the topology of the non-packet data network connecting the plurality of nodes, the non-packet data network forming a data plane network. The method comprises computing a segment routing path to be taken for non-packet traffic data through the data plane network, wherein the segment routing path is computed using segment identifiers, SIDs, relating to a data communication network, DCN, coupled to the plurality of nodes. The method comprises sending the computed segment routing path to an ingress node of the data plane network.

Abstract: A method of determining a path in an optical server network (31) comprises obtaining an indication of an amount of premium traffic from a client network (21). The method further comprises considering paths (48) utilising an elastic capability of one or more network elements (30) of the optical server network, and selecting a path from the considered paths, wherein the path is selected based at least partially on having at least a capacity to carry the amount of premium traffic.