Abstract: A method of identifying an egress point to a network location in a data communications network comprising a plurality of nodes and links there between comprises the step, performed at the identifying node, of receiving a notification through the network advertising an adjacency to a network location. The method further comprises the steps, performed at the identifying node, of deriving from the notification adjacency information and identifying, from the adjacency information, the egress point.

Abstract: A method is disclosed of forwarding data in a data communications network comprising a plurality of nodes and links therebetween, each link having an associated usage cost and a load capacity. A forwarding node identifies a lowest cost route, comprising one or more links, to a destination node. If a plurality of lowest cost routes is identified, then the forwarding node allocates data for forwarding along each of the lowest cost routes dependent on a relative load capacity of that route.

Abstract: A method is disclosed for computing routing information for a data communications network comprising a plurality of nodes. The method comprises the step performed at a computing node of receiving from a remote node in the network a routing information update representing a change of state of the network. The method further comprises processing the update to identify a change of state type and setting, dependent on the change of state type, a delay interval after which routing information is to be computed from the update.

Abstract: A method is disclosed for constructing a backup route from a source node around an adjacent component. The source node derives a first set of nodes reachable from it without traversing the adjacent component and a second set of nodes from which a neighbor node of adjacent components is reachable without traversing the adjacent component. The source node then constructs a backup route via an intermediate node in the intersection of the first and second sets.

Abstract: A method of advertising repair capability in a network repair scheme using network repair addresses for repairing around a repairable network component in a data communications network having, as components, nodes and links therebetween, comprises establishing whether an alternate repair path is available around a repairable component. If such a repair path is available, the method further comprises issuing a corresponding notification to nodes in the network.

Abstract: In an example embodiment, a method is provided that receives a broadcast of available bandwidth from a first routing device. A congestion of traffic is detected along a downstream path to a second routing device. This second routing device is an immediate downstream neighbor. As such, an alternate path is established to the second routing device by way of the first routing device based on the available bandwidth in the network and a portion of the traffic is transmitted along the alternate path.

Abstract: A method and apparatus are disclosed for generating routing information in a data communications network. A first network element (such as a router) receives information relating to a second network element, such as another node or a network link. In response, the first network element determines whether the information relating to the second network element indicates a change in the network. When information relating to a second network element indicates a change in the network, the first network element determines a new shortest path through the network from the first network element for each network element in the network. After a delay, the first network element updates routing information for the first network element based on the new shortest path for the first network element. Preferably the delay is proportional to the distance of the first network element from the second network element.

Abstract: A method of constructing a forwarding information structure for forwarding data in a data communications network comprising as components and links therebetween comprises the step, performed at a constructing node, of detecting a component change. The method further comprises the step, performed at a constructing node, of assessing the extent of a corresponding change required to an existing forwarding information structure at the constructing node.

Abstract: In an example embodiment, a multicast tree is accessed. The multicast tree defines one or more destination label switch routers and paths from a source label switch router to the destination label switch routers. Multicast addresses are then transmitted to the destination label switch routers. In an example embodiment, upon receipt of the multicast addresses, a request to update the multicast tree is transmitted. The request includes the identifier of the label switch router that originated the request.

Abstract: One or more sets of routing information are maintained. A network topology change indication of a progressive series of network changes is received, with at least one more associated network topology change indication of the progressive series of network changes expected to be received in the future. An updated set of routing information is computed based on the network topology change indication, and a determination is made as to whether or not the updated set of routing information changes nexthop information for one or more routes. In response to determining that the new set of routing information does not change nexthop information for said one or more routes and given the expectation of at least one more associated network topology change indication of the progressive series of network changes is expected to be received in the future, the routing information is not updated based on the updated set of routing information.

Abstract: A method and apparatus are disclosed for establishing adjacencies on a network, the method comprising, at a first node of the network, sending hello packets on the network and receiving hello packets from other nodes on the network on the basis of the received hello packets. The node then sends a link-state packet without adjacency information and without an overload bit set. The node then interrogates a link-state adjacency table and, when only one adjacency is listed in the link-state table, sends a further link-state packet with the adjacency information and the overload bit set. On convergence of a forward cache, the node sends a further link-state packet with adjacency information and without the overload bit set.