# US 2021/0243076 A1 · Advanced link tracking for virtual cluster switching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243076 A1 - Document ID: US20210243076A1 - Status: Published application - Kind: A1 - Application number: 17/175,537 - Filed: 2021-02-12 - Published: 2021-08-05 - Earliest claimed: 2010-06-07 - Assignees: Avago Technologies International Sales Pte. Limited - Applicants: Avago Technologies International Sales Pte. Limited - Inventors: Suresh Vobbilisetty; Phanidhar Koganti - Web page: https://patentgrep.com/patent/US20210243076A1 ## CPC - H04L 41/0677: Localisation of faults - 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 45/586: of virtual routers - H04L 49/555: {Error detection} - H04L 49/70: {Virtual switches} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract One embodiment of the present invention provides a switch system. The switch includes a port that couples to a server hosting a number of virtual machines. The switch also includes a link tracking module. During operation, the link tracking module determines that reachability to at least one end host coupled to a virtual cluster switch of which the switch is a member is disrupted. The link tracking module then determines that at least one virtual machine coupled to the port is affected by the disrupted reachability, and communicates to the server hosting the affected virtual machine about the disrupted reachability. ## Claims ### Claim 1 A switch, comprising: one or more ports; processing circuitry configured to: detect a failure which affects reachability between the switch and a second switch in a network of interconnected switches, wherein the network of interconnected switches is identified by an identifier; in response to determining that the failure affects reachability to an end host, identify a port via which the end host is reachable; and use the identified port as an egress port for a notification message including information regarding the failure, wherein the notification message is destined to a hypervisor managing a virtual machine to allow the hypervisor to reconfigure the virtual machine. ### Claim 2 (depends on 1) The switch of claim 1, in response to determining that the failure does not affect reachability to the end host, the processing circuitry is further configured to determine that a routing update in the network of interconnected switches can resolve the failure. ### Claim 3 (depends on 1) The switch of claim 1, wherein the virtual machine is hosted in the end host, and reachability to the end host affects reachability to the virtual machine. ### Claim 4 (depends on 3) The switch of claim 3, wherein the processing circuitry is further configured to construct a second notification message including reachability information associated with the failure, wherein the second notification message is destined to a second hypervisor residing in a second end host. ### Claim 5 (depends on 3) The switch of claim 3, wherein the reachability to the virtual machine includes reachability between the virtual machine and a second virtual machine. ### Claim 6 (depends on 1) The switch of claim 1, wherein the processing circuitry is further configured to monitor a link between the switch and the second switch for failure. ### Claim 7 (depends on 1) The switch of claim 1, further comprising an encapsulator configured to encapsulate a packet with an encapsulation header, wherein the encapsulated packet is forwardable in the network of interconnected switches based on the encapsulation header. ### Claim 8 A method, comprising: detecting a failure which affects reachability between a switch and a second switch in a network of interconnected switches, wherein the network of interconnected switches is identified by an identifier; in response to determining that the failure affects reachability to an end host, identifying a port via which the end host is reachable; and using the identified port as an egress port for a notification message including information regarding the failure, wherein the notification message is destined to a hypervisor managing a virtual machine to allow the hypervisor to reconfigure the virtual machine. ### Claim 9 (depends on 8) The method of claim 8, further comprising, in response to determining that the failure does not affect reachability to the end host, determining that a routing update in the network of interconnected switches can resolve the failure. ### Claim 10 (depends on 8) The method of claim 8, wherein the virtual machine is hosted in the end host, and reachability to the end host affects reachability to the virtual machine. ### Claim 11 (depends on 10) The method of claim 10, further comprising constructing a second notification message comprising reachability information associated with the failure, wherein the second notification message is destined to a second hypervisor residing in a second end host. ### Claim 12 (depends on 10) The method of claim 10, wherein the reachability to the virtual machine includes reachability between the virtual machine and a second virtual machine. ### Claim 13 (depends on 8) The method of claim 8, further comprising monitoring a link between the switch and the second switch for failure. ### Claim 14 (depends on 8) The method of claim 8, further comprising encapsulating a packet with an encapsulation header, wherein the encapsulated packet is forwardable in the network of interconnected switches based on the encapsulation header. ### Claim 15 A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method, the method comprising: detecting a failure which affects reachability between a switch and a second switch in a network of interconnected switches, wherein the network of interconnected switches is identified by an identifier; in response to determining that the failure affects reachability to an end host, identifying a port via which the end host is reachable; and using the identified port as an egress port for a notification message including information regarding the failure, wherein the notification message is destined to a hypervisor managing a virtual machine to allow the hypervisor to reconfigure the virtual machine. ### Claim 16 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises, in response to determining that the failure does not affect reachability to the end host, determining that a routing update in the network of interconnected switches can resolve the failure. ### Claim 17 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein the virtual machine is hosted in the end host, and reachability to the end host affects reachability to the virtual machine. ### Claim 18 (depends on 17) The non-transitory computer-readable storage medium of claim 17, wherein the method further comprises constructing a second notification message including reachability information associated with the failure, wherein the second notification message is destined to a second hypervisor residing in a second end host. ### Claim 19 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises monitoring a link between the switch and the second switch for failure. ### Claim 20 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein the method further comprises encapsulating a packet with an encapsulation header, wherein the encapsulated packet is forwardable in the network of interconnected switches based on the encapsulation header.