# US 10,873,527 B2 · Link protection method in SDN, switching device, and network controller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,527 B2 - Document ID: US10873527B2 - Status: Granted - Kind: B2 - Application number: 15/668,484 - Filed: 2017-08-03 - Published: 2017-12-14 - Granted: 2020-12-22 - Earliest claimed: 2015-02-03 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Peilin Yang; Hengcheng Zhang; Tao Han - Web page: https://patentgrep.com/patent/US10873527B2 ## CPC - H04L 45/28: using route fault recovery - H04L 41/0663: Performing the actions predefined by failover planning, e.g. switching to standby network elements - H04L 41/0668: by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure - H04L 41/0836: {to enhance reliability, e.g. reduce downtime} - H04L 41/0895: Configuration of virtualised networks or elements, e.g. virtualised network function or OpenFlow elements - H04L 41/40: using virtualisation of network functions or resources, e.g. SDN or NFV entities - H04L 45/22: {Alternate routing} - H04L 45/64: using an overlay routing layer - H04L 47/728: {for backup paths} - H04L 47/746: {Reaction triggered by a failure} - H04L 12/4641: {Virtual LANs, VLANs, e.g. virtual private networks [VPN] (LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272)} - H04L 45/38: {Flow based routing} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A link protection method in a software-defined networking (SDN), a corresponding switching device and network controller, where the method includes receiving, by a first switching device in the SDN, first information from a network controller in the SDN and link protection information, where the first information establishes a communication link between the first switching device and a destination device, and the link protection information instructs the first switching device to proactively perform primary-to-secondary link switching when a link is faulty, establishing, by the first switching device, the communication link with the destination device according to the first information, and determining, by the first switching device according to the link protection information, that the first switching device proactively performs the primary-to-secondary link switching. ## Claims ### Claim 1 A link-protection method in a software-defined network (SDN), the link-protection method comprising: receiving, by a first switching device in the SDN, first information from a network controller in the SDN and link protection information, wherein the first information includes a network link signaling negotiation result between an SDN controller (SNC) and a first destination device and a network link signaling negotiation result between the SNC and a second destination device, wherein the first information further instructs the first switching device to establish communication links between the first switching device and the first destination device and between the first switching device and the second destination device, wherein the link protection information instructs the first switching device to proactively perform primary-to-secondary link switching when a link is faulty, wherein the first information comprises type information of a to-be-established link and status information of the to-be-established link, and wherein the type information of the to-be-established link comprises information about a virtual private local area network service (VPLS); establishing, by the first switching device, a primary link with the first destination device and a secondary link with the second destination device according to the network link signaling negotiation results between the SNC, the first destination device, and the second destination device; and determining, by the first switching device according to the link protection information, to automatically and proactively perform the primary-to-secondary link switching. ### Claim 2 (depends on 1) The link-protection method of claim 1, wherein determining to automatically and proactively perform the primary-to-secondary link switching comprises: determining, by the first switching device, that the primary link between the first switching device and the first destination device is faulty; and switching, by the first switching device, a working link from the primary link to the secondary link according to the link protection information. ### Claim 3 (depends on 2) The link-protection method of claim 2, wherein determining that the primary link between the first switching device and the first destination device is faulty comprises determining, by the first switching device by detection, that the primary link between the first switching device and the first destination device is faulty. ### Claim 4 (depends on 2) The link-protection method of claim 2, wherein after switching the working link from the primary link to the secondary link, the method further comprises sending, by the first switching device, a switching notification message to the network controller to notify the network controller that the first switching device has switched the working link from the primary link to the secondary link. ### Claim 5 (depends on 2) The link-protection method of claim 2, wherein determining that the primary link between the first switching device and the first destination device is faulty comprises receiving, by the first switching device, a fault notification message from the network controller, and wherein the notification message notifies the first switching device that the primary link between the first switching device and the first destination device is faulty. ### Claim 6 A link-protection method in a software-defined network (SDN), the link-protection method comprising: performing, by a network controller in the SDN, network link signaling negotiation to establish a communications link with a first destination device; performing, by the network controller, network link signaling negotiation to establish a communications link with a second destination device; obtaining, by the network controller, first information and link protection information, wherein the first information includes a network link signaling negotiation result between the network controller and the first destination device and a network link signaling negotiation result between the network controller and the second destination device, wherein the first information further instructs a first switching device in the SDN to establish communication links between the first switching device and the first destination device and between the first switching device and the second destination device, wherein the link protection information instructs the first switching device to proactively and automatically perform primary-to-secondary link switching when a link is faulty, wherein the first switching device is controlled by the network controller, and wherein the first information contains type information of a to-be-established link and status information of the to-be-established link, and at least one of information about an access controller (AC) side link, an AC bound interface, a pseudowire (PW) side link, PW incoming label information, PW outgoing label information, peer address information, a time to live (TTL) value, a maximum transmission unit (MTU), or a link encapsulation type; and sending, by the network controller, the first information and the link protection information to the first switching device to instruct the first switching device to establish a primary link with a first destination device and a secondary link with a second destination device according to the network link signaling negotiation results between the network controller, the first destination device, and the second destination device. ### Claim 7 (depends on 6) The link-protection method of claim 6, wherein after sending the first information and the link protection information to the first switching device, the method further comprises receiving, by the network controller, a switching notification message from the first switching device, and wherein the switching notification message notifies the network controller that the first switching device has switched a working link from the primary link to the secondary link. ### Claim 8 (depends on 7) The link-protection method of claim 7, wherein before receiving the switching notification message from the first switching device, the method further comprises: detecting, by the network controller, the primary link; and sending, by the network controller, a fault notification message to the first switching device when determining, by detection, that the primary link is faulty. ### Claim 9 A switching device, comprising: a bus; a memory coupled to the bus and configured to store an instruction; a receiver coupled to the bus and configured to receive first information and link protection information from a network controller in software-defined networking (SDN), wherein the first information includes a network link signaling negotiation result between an SDN controller (SNC) and a first destination device and a network link signaling negotiation result between the SNC and a second destination device, wherein the first information further instructs the switching device to establish communication links between the switching device and the first destination device and between the switching device and the second destination device, wherein the link protection information instructs the switching device to proactively and automatically perform primary-to-secondary link switching when a link is faulty, wherein the first information contains the type information of a to-be-established link, and status information of the to-be-established link, and wherein the type information of the to-be-established link further comprises information about a virtual private local area network service (VPLS), a single-end or a multi-end type; and a processor coupled to the bus, wherein the instruction causes the processor to be configured to: establish a primary link with the first destination device and a secondary link with the second destination device according to the network link signaling negotiation results between the SNC, the first destination device, and the second destination device; and determine, according to the link protection information, instructions to proactively and automatically perform the primary-to-secondary link switching. ### Claim 10 (depends on 9) The switching device of claim 9, wherein the instruction further causes the processor to be configured to: determine that the primary link between the switching device and the first destination device is faulty; and switch a working link from the primary link to the secondary link according to the link protection information. ### Claim 11 (depends on 10) The switching device of claim 10, wherein the instruction further causes the processor to be configured to determine, by detection, that the primary link between the switching device and the first destination device is faulty. ### Claim 12 (depends on 10) The switching device of claim 10, further comprising a transmitter coupled to the memory, the processor, and the receiver by the bus, wherein the transmitter is configured to send a switching notification message to the network controller after the processor switches the working link from the primary link to the secondary link to notify the network controller that the switching device has switched the working link from the primary link to the secondary link. ### Claim 13 (depends on 10) The switching device of claim 10, wherein the instruction further causes the processor to be configured to receive a fault notification message from the network controller, and wherein the fault notification message notifies the switching device that the primary link between the switching device and the first destination device is faulty. ### Claim 14 A network controller, comprising: a bus; a transmitter coupled to the bus; a receiver coupled to the bus; a memory coupled to the bus and storing at least one instruction; a processor coupled to the bus, wherein the at least one instruction causes the processor to be configured to: perform network link signaling negotiation to establish communications with a first destination device via the transmitter and receiver; perform network link signaling negotiation to establish communications with a second destination device via the transmitter and receiver; obtain first information and link protection information, wherein the first information includes a network link signaling negotiation result between the network controller and the first destination device and a network link signaling negotiation result between the network controller and the second destination device, wherein the first information further instructs a first switching device in a software defined network (SDN) to establish communication links between the first switching device and the first destination device and between the first switching device and the second destination device, wherein the link protection information instructs the first switching device to proactively and automatically perform primary-to-secondary link switching when a link is faulty, wherein the first information contains the type information of a to-be-established link and status information of the to-be-established link, wherein the type information of the to-be-established link further comprises at least one of information about, a single-end or a multi-end type, and wherein the first switching device is controlled by the network controller; and send, via the transmitter, the first information and the link protection information to the first switching device to instruct the first switching device to establish a primary link with the first destination device and a secondary link with the second destination device according to the network link signaling negotiation results between the network controller, the first destination device, and the second destination device. ### Claim 15 (depends on 14) The network controller of claim 14, wherein the receiver is configured to receive a switching notification message from the first switching device after the transmitter sends the first information and the link protection information to the first switching device, and wherein the switching notification message notifies the network controller that the first switching device has switched a working link from the primary link to the secondary link. ### Claim 16 (depends on 15) The network controller of claim 15, wherein the at least one instruction further causes the processor to be configured to: detect the primary link before the receiver receives the switching notification message from the first switching device; and send a fault notification message to the first switching device using the transmitter when determining, by detection, that the primary link is faulty. ### Claim 17 (depends on 15) The network controller of claim 15, wherein the type information of a to-be-established link comprises type information of to-be-established links between the first switching device and the first and second destination devices. ### Claim 18 (depends on 17) The network controller of claim 17, wherein the first information comprises at least one of the type information and a link attribute information, and wherein the type information comprises a virtual private local area network (LAN) service (VPLS). ### Claim 19 (depends on 18) The network controller of claim 18, wherein the link attribute information comprises information about an access controller (AC) side link, an AC bound interface, a pseudowire (PW) side link, PW incoming label information, PW outgoing label information, peer address information, a time to live (TTL) value, a maximum transmission unit (MTU), or a link encapsulation type. ### Claim 20 (depends on 15) The network controller of claim 15, wherein the first information comprises link attribute information.