Abstract: A method of designing a network given a set of network nodes, a set of adjacencies defining which nodes can be connected together directly and so are topologically adjacent and a traffic matrix comprising a plurality of entries each indicating a source node, a destination node and a number being the number of connections from the source node to the destination node that are to be present in the network; the method comprising the steps of: simulating the network nodes and the adjacencies thereof to generate a simulated network; simulating applying the traffic matrix entry by entry, each application of an entry causing a number of links consistent with the entry to be simulated between the source and destination nodes indicated in the entry, via a chain of topologically adjacent nodes; simulating the effect of at least one failure on the simulated network, including simulating the re-routing of the links onto a replacement chain where the chain is broken; determining the number of links between each pair of top

Abstract: In a connection-oriented network a point-to-multipoint working path is established between a source node and a plurality of destination nodes using a number of working path intermediate nodes. A point-to-multipoint protection path is established for possible points of failure in the working path. Each protection path connects a first working path intermediate node upstream of a point of failure and destination nodes of the working path downstream of the first working path intermediate node. The point-to-multipoint protection path only connects to destination nodes of the working path and working path intermediate nodes which must be transited to reach the destination nodes of the working path.

Abstract: A method for multicast routing for a telecommunications network comprising a plurality of communication nodes interconnected by multiple paths, for the establishment of a multicasting connection between a source node and a plurality of destination nodes, in which the destination nodes are informed that a multicast connection request is arriving from a particular source. Each destination node then sends a connection request to the source, and these requests are processed and relayed by each node within the network. The requests are propagated from node to node until they reach the source node, carrying the information on the cost accumulated along the path. Finally, the source node, having received the information on the costs of the possible paths, selects the path which has a satisfactory cost.

Abstract: A data communications system has a plurality of nodes connected by a plurality of links. A subset of the links and nodes forms a worker path for carrying worker data through the communications system, and a further subset of links and nodes provides a protection path for carrying other data in the absence of a fault in the worker path and for providing an alternative path for the worker data in the event of a fault in the worker path. The alternative path is predetermined prior to the detection of a fault in the worker path.

Abstract: A network arranged to implement label switched paths, comprising: an ingress label edge router (LER), atleast one label switching router (LSR), and an egress LER, in which the ingress LER is connected to the egress LER via one or more of the LSRs. In said network the ingress LER is arranged to transmit, in use, a path message for setting up a bidirectional label switched path (LSP) from the ingress LER to the egress LER via at least one LSR in response for a request for such an LSP. The path message is transmitted over the path of the LSP to be created, in which the path message comprises a first parameter indicative of the bandwidth to be assigned to data traversing the LSP in a first, downstream, direction from ingress LER to egress LER and a second parameter indicative of the bandwidth to be assigned to data traversing the LSP in an opposite, upstream, direction, in which the upstream and downstream bandwidths are different.

Abstract: Routing method for paths in an optical network that includes nodes having limited conversion and/or regeneration capability and in which a routing algorithm based on considerations of cost of the links is employed and in which with the nodes is associated cost information that includes conversion and/or regeneration costs. Such conversion and/or regeneration cost information is considered in the routing algorithm together with the other cost information for calculation of the routings.

Abstract: A method of path protection for a connection-oriented packet switched communications network is described using a protection hub in communication with a worker hub via a core protection path. Both the worker hub and the protection hub communicate with at least one provider edge device via a respective worker and protection paths. The method detects a failure in the communications network, indicates the failure to the at least one of the provider edge device, the worker hub, and the protection hub. The method then employs the core protection path if a failure occurs along a worker path is detected, or a worker path and a protection path in parallel if a failure occurs along the core protection path.

Abstract: A communication network protection system made up of interconnected networks, at least one of which has an automatic control plane (for example ASTN) among which are terminal interconnecting nodes. With the terminal interconnection nodes, termed primary nodes, are associated corresponding secondary terminal nodes wherein a secondary terminal node is used to realize a protection circuit in case of failure of the associated primary node.

Abstract: A network system comprises at least one input TNE (10) and one output TNE (11) interconnected by circuits in the network (20). Each TNE in the protection step comprises a traffic selector (22, 23) switchable between listening to the traffic input from a work circuit (13, 14) and listening to the traffic input from a reset circuit (18, 19) and a Split module (21, 24) allowing sending of a same traffic output either to a work circuit or to a reset circuit. Each TNE comprises in addition an agent (25, 26) termed ASTN agent commanding activation and deactivation of the reset circuit and switching of the traffic selector between work circuit and reset circuit.

Abstract: A method for multicast routing for a telecommunications network comprising a plurality of communication nodes interconnected by multiple paths, for the establishment of a multicasting connection between a source node and a plurality of destination nodes, in which the destination nodes are informed that a multicast connection request is arriving from a particular source. Each destination node then sends a connection request to the source, and these requests are processed and relayed by each node within the network. The requests are propagated from node to node until they reach the source node, carrying the information on the cost accumulated along the path. Finally, the source node, having received the information on the costs of the possible paths, selects the path which has a satisfactory cost.

Abstract: A data communications system has a plurality of nodes connected by a plurality of links. A subset of the links and nodes forms a worker path for carrying worker data through the communications system, and a further subset of links and nodes provides a protection path for carrying other data in the absence of a fault in the worker path and for providing an alternative path for the worker data in the event of a fault in the worker path. The alternative path is predetermined prior to the detection of a fault in the worker path.

Abstract: A control method or protocol for the control scheme of a connection oriented network such as the automatically switched transport networks (ASTN G.807). Such a protocol provides a set of control functions with the purpose of setting and releasing connections through the transport network. Differently from protocols based on Link State Packet such as ATM, PNNI or MPLS, this protocol is based on a fully shared network database where each node keeps only its own information. This greatly reduces the required computations imposed on the single node.