A method and system for protection switching distributes responsibility for action between a central controller and network elements at endpoints of a linear point-to-point network path. The central controller may be configured to support protection switching by network elements at endpoints of a linear point-to-point path, such that the network elements perform protection switching independently and without direct involvement and/or dependency of the central controller. Simultaneously, the central controller may remain aware of network element actions, events, and states with regard to protection switching, by receiving corresponding notifications from the network elements.

A method for communication includes, in a first network switch that is part of a communication network having a topology, detecting a compromised ability to forward a flow of packets originating from a source endpoint to a destination endpoint. In response to detecting the compromised ability, the first network switch identifies, based on the topology, a second network switch that lies on a current route of the flow, and also lies on one or more alternative routes from the source endpoint to the destination endpoint that do not traverse the first network switch. A notification, which is addressed individually to the second network switch and requests the second network switch to reroute the flow, is sent from the first network switch.

A communication network control system (1) eliminates, in a communication network (G) in which a plurality of nodes (N.sub.i) are connected via a plurality of links (2), a node (N.sub.x) having a trouble and implements a reconnection in the communication network (G). The nodes (N.sub.i) each comprise: a path information calculation means (3) that calculates path information of the communication network (G) when a trouble occurs in an adjacent node (N.sub.x); an order information calculation means (4) that calculates, for a set of reconnection destination candidate nodes (N.sub.i), order information in which the reconnection destination candidate nodes are sequenced in order of inter-node distance on the path information calculated by the path information calculation means (3); and a determination information calculation means (5) that calculates, on the basis of the order information calculated by the order information calculation means (4), such a combination that the inter-node distance on the path information in the whole communication network (G) after the reconnection becomes larger and that determines the calculated combination as a reconnection destination node of the local node (N.sub.i).

Technologies are generally described for a failure recovery scheme for a cloud system. In some examples, the cloud system may include one or more computing nodes, and one or more network switches configured to relay one or more packets among the one or more computing nodes. A respective one of the computing nodes may include a first processor configured to process the one or more packets to communicate with at least one of the network switches, and a second processor configured to process the one or more packets to communicate with at least one of the other computing nodes in the cloud system.

Techniques for performing efficient topology failure detection in SDN networks are provided. In one embodiment, a computer system (e.g., an SDN controller) can transmit a first message to a first network device, where the first message instructs the first network device to begin sending probe packets to a second network device at a predetermined rate. The computer system can further transmit a second message to the second network device, where the second message instructs the second network device to monitor for the probe packets sent by the first network device and to notify the computer system when one or more of the probe packets are not received by the second network device. If the computer system receives such a notification from the second network device, the computer system can determine that a port, link, or node failure has occurred between the first and second network devices.

Examples relate to fast failover recovery in software defined networks. In some examples, a failure in a first primary tree is detected during data transmission of a data packet, where the primary tree is associated with a first group entry that is configured to direct each of the data packets to one of a first set of destination devices. A notification of the failure is sent to a remote controller device, where the remote controller device identifies backup trees of the route trees that does not include the failure. After the remote controller device updates the first group entry to be associated with a first backup tree that minimizes congestion, each of the data packets are sent to one of a second set of destination devices that are associated with the first backup tree.

A method is presented for supporting SNCP over a packet network connecting to two SDH sub-networks and transporting one or more SDH paths that are SNCP-protected in both SDH sub-networks. The packet network connects to each of two sub-network interconnection points by a working path and a protection path. The packet sub-network may provide the same type of path protection as an SDH sub-network using SNCP, while avoiding bandwidth duplication.

A method performed by a network node. The method includes detecting a loss of connection at an incoming interface to an upstream neighbor of the network node, where the network node is in a multicast communication network that includes a multicast tree to provide connectivity from a common source node to one or more multicast recipient nodes. The multicast communication network further includes a set of one or more secondary paths to provide redundancy to the multicast tree, and sending a notification packet downstream toward the one or more multicast recipient nodes when the network node cannot re-route the multicast data traffic to allow the multicast data traffic to be received by the multicast recipient nodes, wherein the notification packet causes one or more downstream nodes to switch multicast reception to one or more of the set of one or more secondary paths to re-route the multicast data traffic.

Techniques are described for providing managed computer networks. In some situations, the techniques include managing communications for computing nodes of a managed computer network by using one or more particular computing nodes of the managed computer network that are configured to operate as intermediate destinations to handle at least some communications that are sent by and/or directed to one or more other computing nodes of the managed computer network. In addition, the techniques may include managing the communications in accordance with configured failure behavior specified for one or more computing nodes of the computer network, such as specified failure behavior for a computing node configured to operate as an intermediate destination that indicates how communications that would otherwise be routed via the intermediate destination computing node are to be handled if the intermediate destination computing node fails or is otherwise unavailable (e.g., to block or allow such communications).

The embodiments disclosed herein provide fast recovery of a network signal path by, in the event of a failure or unacceptable degradation in a signal in the original network path, diverting the optical signal passing through the network to a preselected bypass optical path which is maintained in a warm or operational state. The optical elements on the bypass optical path are available network resources which may, during part or all of the time the bypass path is designated for a node in the primary optical path, be in use to transmit other optical signals in the network. By maintaining the resources in the designated bypass path in a warm or operating state, fast rerouting and recovery of an interrupted signal is possible.