Telefonaktiebolaget Lm Ericsson (publ)

Paolo Rebella

Daniele Ceccarelli

Diego Caviglia

Francesco Fondelli

Massimiliano Maggiari

In one example aspect, a method is provided for tearing down a label switched path (LSP) through a communications network. The method comprises sending a first message towards an egress node of the LSP informing nodes of the LSP and the egress node of a tear down of the LSP, determining that one of the nodes of the LSP has not forwarded the first message along the LSP, and sending a second message to a controller of the communications network to cause the controller to communicate directly with one of the nodes to inform the one of the nodes of the tear down of the LSP.

Tearing down a label switched path through a communications network

A method for routing packet traffic through a network comprising a plurality of network nodes supporting RSVP-TE protocol and Segment Routing protocol. Each of the two protocols is associated with a separate set of labels, the method comprises calculating () a path through the network; checking support () for both protocols at nodes along the calculated path and encoding () the calculated path as a set of Adjacency Segment Identifiers. The method also comprises optimising () a label stack of the calculated path by substituting more than one adjacency SIDs with a node SID if a partial path identified by the substituted adjacency SIDs equals a shortest path. If all nodes along the calculated path support label stack depth equal to or deeper than the optimised label stack () then segment routing is used to set up the path. If a node along the calculated path does not support a label stack depth equal to or deeper than the depth of the optimised label stack () then an Explicit Route Object is used for signalling the calculated path using RSVP-TE ().

Method and apparatus for segment routing and RSVP-TE routing in transport SDN networks

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.

Method and network node for managing resource allocation in traffic restoration

The present invention provides a method for enabling Segment Routing in a multi-domain network comprising a client network domain and a server network domain, where the client network domain is a packet network domain and the server network domain is a connected-oriented network domain. The method comprises assigning a network segment identifier to each of one or more potential paths through the server network domain between a pair of overlay network nodes in the client network domain, wherein the one or more potential paths are not pre-configured and the or each network segment identifier is suitable for inclusion in one or more data packets to indicate to at least one of the pair of overlay network nodes a preselected network segment routing for the one or more data packets. The present invention further provides a method for routing data packets in the multi-domain network. The method, in an overlay network node in the client network domain, comprises receiving one or more data packets, and retrieving a network segment identifier included in at least one of the one or more data packets. The method further comprises determining that the network segment identifier indicates that the one or more data packets should be routed over a pre-selected potential path through the server network domain, and, based on the determining, triggering the server network domain to configure the pre-selected potential path through the server network domain.

Segment routing in a multi-domain network

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.

Segment recovery in connection-oriented network

A method of realigning a node in a label switched network comprising a plurality of nodes and a node with a processor, a memory, and a network interface, for carrying out the method. The method includes periodically maintaining backup path status information for the node, restarting the node, and re-establishing label switched paths with the plurality of nodes using the backup status information. Communication with adjacent nodes is carried out in order to reconcile the path status information with respective path status information in the adjacent nodes in order to establish node realignment preferably judged against a threshold value for path reliability.

Growing community of inventors

Genoa, Italy

Paolo Rebella