Abstract: A computer network processes data packets in the event of a network link failure. The network includes a plurality of routers that deliver data packets to the network via a plurality of links. At least one router includes a protection cycle manager. The protection cycle manager has a protection cycle packet identifier and a protection cycle packet processor. The protection cycle packet identifier identifies, as protection cycle packets, data packets having a specific protection cycle format. The protection cycle packet processor processes protection cycle packets to determine whether the packet destination corresponds to the routing node, and if the packet destination corresponds to the routing node, the protection cycle packet is treated by the routing node as a data packet received from the packet source via the failed link. Otherwise, if the packet destination does not correspond to the routing node, the protection cycle packet is sent to a protection cycle node for the routing node.

Abstract: A communications network comprises a lower transport layer and an upper overlay incorporating a plurality of routers. Adjacencies are defined between respective pairs of routers. Path protection is provided by defining a software model of the overlay of the network and defining in the model a hierarchy of protection levels for the main path. Each protection level is characterised by a respective set of one or more broken adjacencies in the model, the adjacencies to be broken being determined from a knowledge of the underlying topology. A protection level is selected and a protection path avoiding the broken adjacencies associated with that protection level is calculated. If this calculated path is not available in the real network, a lower protection level in the hierarchy is selected and the protection path calculation repeated. The process continues until a suitable protection path is identified.

Abstract: A communications packet network comprises a plurality of nodes interconnected by communication links and in which tunnels are defined for the transport of high quality of service traffic. The network has a set of primary traffic paths for carrying traffic and a set of pre-positioned recovery (protection) traffic paths for carrying traffic in the event of a fault affecting one or more the primary paths. The network incorporates a fault recovery mechanism. In the event of a fault, traffic is switched temporarily to a recovery path. The network then determines a new set of primary and recovery paths taking account of the fault. The traffic is then switched to the new primary paths. The new recovery paths provide protection paths in the event of a further fault. The network nodes at the two ends of a recovery path exchange information over that path so that packets returning to the main path present labels that are recognizable for further routing of those packets.

Abstract: An arrangement and a plug separated from a strip for closing at least one end of a tube to protect the tube against internal dirtying. The plug formed for closing a tube end together with similarly formed plugs is integrally formed one after the other in a predetermined distance from each other in a longitudinal line in a continous strip and is provided with a handle formation by which the plug can be taken out from its mounted position in the tube before or in connection with using the tube.

Abstract: A system, device, and method for bypassing network changes in a communication network pre-computes recovery paths to protect various primary paths. A fast detection mechanism is preferably used to detect network changes quickly, and communications are switched over from the primary paths to the recovery paths in order to bypass network changes. Forwarding tables are preferably frozen as new primary paths are computed, and communications are switched over from the recovery paths to the new primary paths in a coordinated manner in order to avoid temporary loops and invalid routes. New recovery paths are computed to protect the new primary paths.