# US 10,771,390 B2 · Techniques for optimizing egress tunnel router failure scenarios in intelligent wide area networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,771,390 B2 - Document ID: US10771390B2 - Status: Granted - Kind: B2 - Application number: 15/626,150 - Filed: 2017-06-18 - Published: 2018-12-20 - Granted: 2020-09-08 - Earliest claimed: 2017-06-18 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Ravishankar Chandrasekaran; Rex Emmanuel Fernando; Sanjay Kumar Hooda; Jesus Arango - Web page: https://patentgrep.com/patent/US10771390B2 ## CPC - H04L 12/4633: {Interconnection of networks using encapsulation techniques, e.g. tunneling} - H04L 45/02: Topology update or discovery - H04L 47/20: Traffic policing - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract One embodiment of a method includes receiving at a first network node traffic from a second network node; and sending by the first network node to a third network node information identifying the second network node via a Local Area Network (“LAN”) connection between the first and third network nodes. Subsequent to receipt of the information identifying the second network node, the third network node updates a locator table maintained by the third network node to include an entry including the information identifying the second network node received by the third network node from the first network node. Upon receipt by the third network node of a notification that the first network node has failed, the third network node sends an update only to network nodes that have an entry in the locator table indicating that the first network node has failed. ## Claims ### Claim 1 A method comprising: receiving, at a first network node, traffic from a second network node via a first network that is a Location Identifier Separation Protocol (LISP)-enabled network; and in response to receiving the traffic, generating and sending, by the first network node to a third network node, a first update including information identifying the second network node, wherein the first and third network nodes are egress tunnel routers that are peer nodes interconnected via a Local Area Network (“LAN”) connection different from the first network and wherein the information identifying the second network node is sent from the first network node to the third network node via the LAN connection, wherein subsequent to receipt of the information identifying the second network node, the third network node updates a locator table configured using the LISP that is maintained by the third network node to include an entry corresponding to the second network node, wherein the entry includes the information identifying the second network node received by the third network node from the first network node, and wherein based on receipt by the third network node via the LAN connection of a notification that the first network node has failed, the third network node sends a second update, via the first network, only to network nodes including the second network node, that have a corresponding table entry in the locator table indicating that the first network node has failed and to cease communication therewith. ### Claim 2 (depends on 1) The method of claim 1 further comprising: subsequent to receiving the traffic, updating by the first network node, another locator table maintained by the first network to include another entry corresponding to the second network node and including the information identifying the second network node sent by the first network node to the third network node. ### Claim 3 (depends on 1) The method of claim 1, wherein the second network node comprises an ingress tunnel router and is connected to the first network node and to the third network node via the LISP-enabled network. ### Claim 4 (depends on 1) The method of claim 1, wherein the locator table comprises a remote routing locator table and the table entry includes an RLOC of the second network node. ### Claim 5 (depends on 1) The method of claim 1, wherein upon receipt by the third network node via the LAN connection of the notification that the first network node has failed, the third network node sends a plurality of updates only to the network nodes that have the corresponding table entry in the locator table indicating that the first network node has failed and to cease the communication therewith, wherein each of the plurality of updates is sent at a predetermined interval. ### Claim 6 (depends on 1) The method of claim 1, wherein each of the first and third network nodes stores the locator table comprising a remote routing locator table (RLOC), and wherein, based on the receiving the traffic, the first network node updates the RLOC of the first network node and generates and sends the first update so that the third network node updates the RLOC of the third network node. ### Claim 7 (depends on 1) The method of claim 1, wherein sending the second update includes the third network node sending a plurality of second updates to each of one or more network nodes identified in the locator table. ### Claim 8 (depends on 1) The method of claim 1, further comprising: based on the receipt, by the third network node, via the LAN connection, of the notification that the first network node has failed, retrieving, by the third network node, each of a plurality of table entries in the locator table of the third network node, wherein each of the plurality of table entries in the locator table identifies a respective ingress tunnel router (ITR) that is remotely communicating with the first network node via the first network; and sending, by the third network node, via the first network, the second update to each of the respective ITR, indicating that the first network node has failed and to cease the communication therewith. ### Claim 9 One or more non-transitory tangible media that include code for execution and when executed by a processor is operable to perform operations comprising: receiving, at a first network node, traffic from a second network node via a first network that is a Location Identifier Separation Protocol (LISP)-enabled network; and in response to receiving the traffic, generating and sending, by the first network node to a third network node, a first update including information identifying the second network node, wherein the first and third network nodes are egress tunnel routers that are peer nodes interconnected via a Local Area Network (“LAN”) connection different from the first network and wherein the information identifying the second network node is sent from the first network node to the third network node via the LAN connection, wherein subsequent to receipt of the information identifying the second network node, the third network node updates a locator table configured using the LISP that is maintained by the third network node to include an entry corresponding to the second network node, wherein the entry includes the information identifying the second network node received by the third network node from the first network node, and wherein based on receipt by the third network node via the LAN connection of a notification that the first network node has failed, the third network node sends a second update, via the first network, only to network nodes, including the second network node, that have a corresponding table entry in the locator table indicating that the first network node has failed and to cease communication therewith. ### Claim 10 (depends on 9) The media of claim 9, wherein the operations further comprise: subsequent to receiving the traffic, updating, by the first network node, another locator table maintained by the first network to include another entry corresponding to the second network node and including the information identifying the second network node sent by the first network node to the third network node. ### Claim 11 (depends on 9) The media of claim 9, wherein the second network node comprises an ingress tunnel router and is connected to the first network node and to the third network node via the LISP-enabled network. ### Claim 12 (depends on 9) The media of claim 9, wherein the locator table comprises a remote routing locator table and the table entry includes an RLOC of the second network node. ### Claim 13 (depends on 9) The media of claim 9, wherein upon receipt by the third network node via the LAN connection of the notification that the first network node has failed, the third network node sends a plurality of updates only to the network nodes that have the corresponding table entry in the locator table indicating that the first network node has failed and to cease the communication therewith, wherein each of the plurality of updates is sent at a predetermined interval. ### Claim 14 (depends on 9) The media of claim 9, wherein each of the first and third network nodes stores the locator table comprising a remote routing locator table (RLOC) and wherein the operations further comprise, based on the receiving the traffic, updating the RLOC of the first network node and the sending of the update is to update the RLOC of the third network node. ### Claim 15 An apparatus comprising: a memory element configured to store data; and a processor operable to execute instructions associated with the data; the processor configured for: receiving, at a first network node, traffic from a second network node via a first network at a Location Identifier Separation Protocol (LISP)-enabled network; and in response to receiving the traffic, generating and sending, by the first network node to a third network node, a first update including information identifying the second network node, wherein the first and third network nodes are egress tunnel routers that are peer nodes interconnected via a Local Area Network (“LAN”) connection different from the first network and wherein the information identifying the second network node is sent from the first network node to the third network node via the LAN connection, wherein subsequent to receipt of the information identifying the second network node, the third network node updates a locator table configured using the LISP that is maintained by the third network node to include an entry corresponding to the second network node, wherein the entry includes the information identifying the second network node received by the third network node from the first network node, and wherein based on receipt by the third network node via the LAN connection of a notification that the first network node has failed, the third network node sends a second update, via the first network, only to network nodes, including the second network node, that have a corresponding table entry in the locator table indicating that the first network node has failed and to cease communication therewith. ### Claim 16 (depends on 15) The apparatus of claim 15 further configured for: subsequent to receiving the traffic, updating, by the first network node, another locator table maintained by the first network to include another entry corresponding to the second network node and including the information identifying the second network node sent by the first network node to the third network node. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the second network node comprises an ingress tunnel router and is connected to the first network node and to the third network node via the LISP-enabled network. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein the locator table comprises a remote routing locator table and the table entry includes an RLOC of the second network node. ### Claim 19 (depends on 15) The apparatus of claim 15, wherein upon receipt by the third network node via the LAN connection of the notification that the first network node has failed, the third network node sends a plurality of updates only to the network nodes that have the corresponding table entry in the locator table indicating that the first network node has failed and to cease the communication therewith, wherein each of the plurality of updates is sent at a predetermined interval. ### Claim 20 (depends on 15) The apparatus of claim 15, wherein each of the first and third network nodes stores which store the locator table comprising a remote routing locator table (RLOC) and wherein the processor is further configured to, based on the receiving the traffic, update the RLOC of the first network node and send the update so as to update the RLOC of the third network node.