# US 2019/0245779 A1 · Fast control path and data path convergence in layer 2 overlay networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0245779 A1 - Document ID: US20190245779A1 - Status: Published application - Kind: A1 - Application number: 16/317,532 - Filed: 2016-07-25 - Published: 2019-08-08 - Earliest claimed: 2016-07-25 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget Lm Ericsson (Publ) - Inventors: V.S. Jagannadham (Jack) JONNALAGADDA; Sajjad AHMED; Antoni PRZYGIENDA; Pramodh D'SOUZA - Web page: https://patentgrep.com/patent/US20190245779A1 ## CPC - H04L 45/28: using route fault recovery - 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 45/22: {Alternate routing} - H04L 45/32: {Flooding (denial of service attacks H04L63/1458)} - H04L 45/507: {Label distribution} - H04L 45/64: using an overlay routing layer - H04L 45/66: {Layer 2 routing, e.g. in Ethernet based MAN's} - H04L 45/16: Multipoint routing - H04L 2101/677: Multiple interfaces, e.g. multihomed nodes - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Methods and apparatuses for fast convergence in Layer 2 overlay network are described. Forwarding of Layer 2 (L2) traffic addressed to one or more remote L2 destinations is performed according to a remote L2 (RL2) instance, where the RL2 instance identifies a primary path for forwarding the traffic towards the remote L2 destinations, and a provider edge service label (PESL) instance associated with a broadcast domain including one or more network devices for forwarding the L2 traffic towards the L2 destination, and where the PESL instance is identified with a unique immutable PESL instance label. In response to a network event, an update of the RL2 instance is performed. The update results in an update of a data plane for forwarding the L2 traffic without necessitating an update of forwarding table entries for each one of the one or more remote L2 destination. ## Claims ### Claim 1 A method for fast convergence in Layer 2 Overlay network, the method comprising: causing a forwarding of Layer 2 (L2) traffic addressed to one or more remote L2 destinations according to a remote L2 (RL2) instance, wherein the RL2 instance identifies a primary path for forwarding the traffic towards the remote L2 destinations, and a provider edge service label (PESL) instance associated with a broadcast domain including one or more network devices for forwarding the L2 traffic towards the L2 destination, and wherein the PESL instance is identified with a unique immutable PESL instance label; and causing, in response to a network event, an update of the RL2 instance that results in an update of a data plane for forwarding the L2 traffic without necessitating an update of forwarding table entries for each one of the one or more remote L2 destination. ### Claim 2 (depends on 1) The method of claim 1, wherein causing, in response to a network event, the update of the RL2 instance includes: determining a unique immutable RL2 instance handle identifying the RL2 instance associated with the one or more L2 destinations; and causing an update of the data plane based on the unique immutable RL2 instance handle. ### Claim 3 (depends on 1) The method of claim 1, wherein forwarding L2 traffic according to the RL2 instance includes: determining a mode of operation of the RL2 instance, wherein the mode of operation is at least one of an all-active mode or a single-active model; responsive to determining that the mode of operation is the all-active mode, distributing the L2 traffic over the primary path and one or more paths of the PESL instance; and responsive to determining that the mode of operation is the single-active mode, performing the following: responsive to determining that the primary path is reachable, forwarding traffic through the primary path, responsive to determining that the primary path is not reachable, flooding the L2 traffic over the one or more paths of the PESL instance. ### Claim 4 (depends on 1) The method of claim 1, wherein the network event is caused by an L2 destination transitioning from being a multi-homed destination to a single-homed destination. ### Claim 5 (depends on 1) The method of claim 1, wherein the network event is caused by an L2 destination transitioning from being a single-homed destination to a multi-homed destination. ### Claim 6 (depends on 1) The method of claim 1, wherein the network event is caused by an update to the PESL instance. ### Claim 7 (depends on 6) The method of claim 6, wherein the update of the PESL instance includes adding an additional path to the PESL instance. ### Claim 8 A non-transitory computer readable storage medium that provide instructions, which when executed by one or more processors, cause the one or more processors to perform operations enabling a fast control path and data path convergence in Layer 2 overlay networks, the operations comprising: causing a forwarding of Layer 2 (L2) traffic addressed to one or more remote L2 destinations according to a remote L2 (RL2) instance, wherein the RL2 instance identifies a primary path for forwarding the traffic towards the remote L2 destinations, and a provider edge service label (PESL) instance associated with a broadcast domain including one or more network devices for forwarding the L2 traffic towards the L2 destination, and wherein the PESL instance is identified with a unique immutable PESL instance label; and causing, in response to a network event, an update of the RL2 instance that results in an update of a data plane for forwarding the L2 traffic without necessitating an update of forwarding table entries for each one of the one or more remote L2 destination. ### Claim 9 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein causing, in response to a network event, the update of the RL2 instance includes: determining a unique immutable RL2 instance handle identifying the RL2 instance associated with the one or more L2 destinations; and causing an update of the data plane based on the unique immutable RL2 instance handle. ### Claim 10 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein forwarding L2 traffic according to the RL2 instance includes: determining a mode of operation of the RL2 instance, wherein the mode of operation is at least one of an all-active mode or a single-active model; responsive to determining that the mode of operation is the all-active mode, distributing the L2 traffic over the primary path and one or more paths of the PESL instance; and responsive to determining that the mode of operation is the single-active mode, performing the following: responsive to determining that the primary path is reachable, forwarding traffic through the primary path, responsive to determining that the primary path is not reachable, flooding the L2 traffic over the one or more paths of the PESL instance. ### Claim 11 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein the network event is caused by an L2 destination transitioning from being a multi-homed destination to a single-homed destination. ### Claim 12 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein the network event is caused by an L2 destination transitioning from being a single-homed destination to a multi-homed destination. ### Claim 13 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein the network event is caused by an update to the PESL instance. ### Claim 14 (depends on 13) The non-transitory computer readable storage medium of claim 13, wherein the update of the PESL instance includes adding an additional path to the PESL instance.