# US 8,155,028 B2 · Method and apparatus for providing full logical connectivity in MPLS networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,155,028 B2 - Document ID: US8155028B2 - Status: Granted - Kind: B2 - Application number: 12/049,743 - Filed: 2008-03-17 - Published: 2009-09-17 - Granted: 2012-04-10 - Earliest claimed: 2008-03-17 - Assignees: Alcatel Lucent - Inventors: Rateb Abu-Hamdeh; Joël Calippe; Zihuang Wang - Web page: https://patentgrep.com/patent/US8155028B2 ## CPC - H04L 41/0803: Configuration setting - H04L 41/12: Discovery or management of network topologies - H04L 45/02: Topology update or discovery - H04L 45/50: using label swapping, e.g. multi-protocol label switch [MPLS] - H04L 43/0811: by checking connectivity - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The invention includes a method and apparatus for configuring logical connectivity for a network comprising a plurality of nodes. A method includes determining a physical topology of the network, determining a set of LSP paths based on the physical topology of the network, and determining a set of LSPs using the set of LSP paths, where the set of LSPs includes a plurality of LSPs adapted for providing full logical connectivity between the nodes of the network. The physical topology is determined using information indicative of physical connectivity between nodes of the network. The set of LSP paths includes, for each pair of nodes in the network, at least two logical paths between the nodes of the node pair. The set of LSPs includes a plurality of LSPs adapted for providing full logical connectivity between the nodes of the network. The full logical connectivity between the nodes of the network may be maintained in response to physical topology change events, such as addition of nodes to the network removal of nodes from the network, and the like. ## Claims ### Claim 1 An apparatus for configuring logical connectivity for a network comprising a plurality of nodes, comprising: means for determining a physical topology of the network using information indicative of physical connectivity between nodes of the network; means for determining, based on the physical topology of the network, a set of label switched path (LSP) paths comprising, for each pair of nodes in the network, at least two logical paths between the nodes of the node pair; and means for determining, using the set of LSP paths, a set of LSPs comprising a plurality of LSPs adapted for providing full logical connectivity between the nodes of the network; means for determining a new physical topology of the network in response to a physical topology change event; means for modifying the set of LSP paths based on the new physical topology of the network, wherein the set of LSP paths comprises, for each pair of nodes in the network, at least two logical paths between the nodes of the node pair; means for modifying the set of LSPs based on the new physical topology of the network, wherein the set of LSPs is modified in a manner for maintaining full logical connectivity between the nodes of the network. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the means for determining the physical topology of the network comprises: means for receiving physical connectivity information describing a plurality of physical connections between the nodes of the network; and means for processing the physical connectivity information to determine the physical topology of the network. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the means for determining the physical topology of the network comprises: means for listening to routing update messages exchanged within the network; and means for processing the routing update messages to determine the physical topology of the network. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the means for determining the set of LSP paths comprises: means for selecting each of the nodes of the network as a source node; means for determining, for each node selected as a source node, for each of the other ones of the nodes of the network, each of at least one path from the selected source node to the other one of the nodes; and means for adding the determined paths for each source node to the set of LSP paths. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the means for determining the set of LSPs comprises: means for selecting ones of the LSP paths from the set of LSP paths, wherein the selected ones of the LSP paths are adapted to provide full logical connectivity between the nodes of the network. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the means for determining the set of LSPs comprises: means for selecting, for each pair of nodes in the network, a first one of the LSP paths providing a logical path between the nodes in a first direction and a second one of the LSP paths providing a logical path between the nodes in a second direction. ### Claim 7 (depends on 1) The apparatus of claim 1, further comprising: means for generating configuration information adapted for configuring the nodes of the network to support the LSPs; and means for propagating the configuration information toward the nodes of the network. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein, for each LSP, the configuration information includes at least one of a hops list to be used for the LSP and endpoint information to be used for the LSP. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the LSPs comprise primary LSPs, the apparatus further comprising: means for determining at least one additional LSP using the set of LSPs and the set of LSP paths. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the at least one additional LSP comprises at least one of at least one secondary LSP and at least one fast reroute (FRR) LSP protection hops list. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the LSPs comprise at least one of static LSPs, strict dynamic LSPs, and loose dynamic LSPs. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the physical topology change event comprises at least one of an addition of at least one node to the network, a deletion of at least one node from the network, a modification of a location of at least one node within the physical topology, a failure of a physical link, and a failure of a logical connection. ### Claim 13 (depends on 1) The apparatus of claim 1, wherein the means for modifying the set of LSP paths comprises: means for adding at least one new LSP path to the set of LSP paths; means for deleting at least one existing LSP path from the set of LSP paths; and means for modifying at least one existing LSP path of the set of LSP paths based on the new physical topology of the network. ### Claim 14 (depends on 1) The apparatus of claim 1, wherein the means or modifying the set of LSPs comprises: means for adding at least one new LSP to the set of LSPs; means for deleting at least one existing LSP from the set of LSPs; and means for modifying at least one existing LSP of the set of LSPs based on the new physical topology of the network. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the means for modifying the set of LSPs comprises: means for identifying at least one of the LSPs of the set of LSPs that is using an LSP path impacted by the physical topology change event; and means for modifying, for each identified LSP, configuration information associated with the LSP. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the configuration information associated with the LSP comprises a hops list used by the LSP. ### Claim 17 A method for configuring logical connectivity for a network comprising a plurality of nodes, comprising: determining, using a processor, a physical topology of the network using information indicative of physical connectivity between nodes of the network; determining, based on the physical topology of the network, a set of label switched path (LSP) paths comprising, for each pair of nodes in the network, at least two logical paths between the nodes of the node pair; and determining, using the set of LSP paths, a set of LSPs comprising a plurality of LSPs adapted for providing full logical connectivity between the nodes of the network; determining, a new physical topology of the network in response to a physical topology change event; modifying the set of LSP paths based on the physical topology of the network, wherein the set of LSP paths comprises, for each pair of nodes in the network, at least two logical paths between the nodes of the node pair; and modifying the set of LSPs based on the physical topology of the network, wherein the set of LSPs is modified in a manner for maintaining full logical connectivity between the nodes of the network. ### Claim 18 (depends on 17) The method of claim 17, wherein the method is performed autonomously by a computer system. ### Claim 19 (depends on 17) The method of claim 17, wherein the method is performed autonomously by a computer system. ### Claim 20 A method for autonomously determining a physical topology of a network based on logical connectivity of the network, comprising: identifying, using a processor, a plurality of label switched paths (LSPs) configured in the network; determining, for each identified LSP, a hops list used by that LSP for routing traffic within the network; and determining the physical topology of the network using the determined hops lists; determining, a new physical topology of the network in response to a physical topology change event; modifying the set of LSP paths based on the physical topology of the network; and modifying the set of LSPs based on the physical topology of the network, wherein the set of LSPs is modified in a manner for maintaining full logical connectivity between the nodes of the network.