# US 10,771,312 B2 · Failure detection in a data network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,771,312 B2 - Document ID: US10771312B2 - Status: Granted - Kind: B2 - Application number: 15/908,636 - Filed: 2018-02-28 - Published: 2019-08-29 - Granted: 2020-09-08 - Earliest claimed: 2018-02-28 - Assignees: Zte Corporation - Applicants: ZTE Corporation - Inventors: Gregory Mirsky - Web page: https://patentgrep.com/patent/US10771312B2 ## CPC - H04L 67/143: Termination or inactivation of sessions, e.g. event-controlled end of session - H04L 41/0622: {based on time} - H04L 41/0631: using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis - H04L 41/064: {involving time analysis} - H04L 41/0681: Configuration of triggering conditions - H04L 43/0823: Errors, e.g. transmission errors - H04L 43/10: Active monitoring, e.g. heartbeat, ping or trace-route - H04L 43/16: Threshold monitoring - H04L 45/026: {Details of "hello" or keep-alive messages} - H04L 45/72: {Routing based on the source address} - H04L 63/0236: {Filtering by address, protocol, port number or service, e.g. IP-address or URL} - H04L 63/126: {the source of the received data} - H04L 67/145: avoiding end of session, e.g. keep-alive, heartbeats, resumption message or wake-up for inactive or interrupted session - H04L 67/146: Markers for unambiguous identification of a particular session, e.g. session cookie or URL-encoding - H04L 69/28: Timers or timing mechanisms used in protocols - H04L 69/40: for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection (management of faults, events, alarms or notifications in data switching networks H04L41/06) - H04L 45/16: Multipoint routing - H04L 49/201: Multicast operation; Broadcast operation - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A first network node generates a message to be transmitted to a second network node. The message can include a value that identifies a type of the operational session, an identifier of the first network node that can control transmission of packets used during the operational session, and a length of the identifier. Further, the first and second network nodes can operate in an operational session in which the second network node can detect a failure. ## Claims ### Claim 1 A packet communication method, comprising: starting, by a first network node, a timer, wherein the first network node and a second network node operate in an operational session that detects a continuity of path between the first network node and a second network node; receiving a packet by the first network node; performing a first determination that the packet includes a first Internet Protocol (IP) address that is the same as a second IP address of the second network node configured to control a transmission interval of packets; performing a second determination, by the first network node, that the packet includes a first identifier that is the same as a My Discriminator value of the second network node configured to control the transmission interval of the packets; and resetting, after the first determination and the second determination, the timer by the first network node. ### Claim 2 (depends on 1) The packet communication method of claim 1, further comprising: receiving, by the first network node and prior to the receiving of the packet, a message that includes a value that identifies a type of the operational session, the My Discriminator value of the second network node, and a length of the My Discriminator value; and creating, by the first network node after receiving the message, the operational session. ### Claim 3 (depends on 1) The packet communication method of claim 1, further comprising: closing, by the first network node, the operational session in response to receiving a message with an absence of a value that identifies a type of the operational session, the My Discriminator value of the second network node, and a length of the My Discriminator value. ### Claim 4 (depends on 1) The packet communication method of claim 1, wherein the packet is received by the first network node while the timer is running. ### Claim 5 (depends on 1) The packet communication method of claim 1, further comprising: sending, by the first network node after an expiration of the timer, another packet to the second network node, wherein the another packet includes a status field that indicates that the operational session is inactive. ### Claim 6 (depends on 1) The packet communication method of claim 1, further comprising: dropping the packet in response to determining that the first identifier is different from the My Discriminator value of the second network node; and dropping the packet in response to determining that the first IP address included in the packet is different from the second IP address of the second network node. ### Claim 7 (depends on 1) The packet communication method of claim 1, wherein the first network node and the second network node operate in a Protocol Independent Multicast Sparse Mode (PIM-SM). ### Claim 8 (depends on 1) The packet communication method of claim 1, wherein the operational session is a Bidirectional Forwarding Detection (BFD) session. ### Claim 9 (depends on 1) The packet communication method of claim 1, wherein the second network node includes a Designated Router (DR) or a Backup Designated Router (BDR). ### Claim 10 (depends on 1) The packet communication method of claim 1, wherein a value for the timer is determined without performing a negotiation with the second network node. ### Claim 11 A network node, comprising: a processor configured to: start a timer, wherein the network node and another network node are configured to operate in an operational session that detects a continuity of path between the network node and the another network node; receive a packet; perform a first determination that the packet includes a first Internet Protocol (IP) address that is the same as a second IP address of the another network node configured to control a transmission interval of packets; perform a second determination that the packet includes a first identifier that is the same as a My Discriminator value of the another network node configured to control the transmission interval of the packets; and reset, after the first determination and the second determination, the timer. ### Claim 12 (depends on 11) The network node of claim 11, wherein the processor is further configured to: receive, prior to the received packet, a message that includes a value that identifies a type of the operational session, the My Discriminator value of the another network node, and a length of the My Discriminator value; and create, by the first network node after receiving the message, the operational session. ### Claim 13 (depends on 11) The network node of claim 11, wherein the processor is further configured to: close the operational session in response to receiving a message with an absence of a value that identifies a type of the operational session, the My Discriminator value of the another network node, and a length of the My Discriminator value. ### Claim 14 (depends on 11) The network node of claim 11, wherein the packet is received by the network node while the timer is running. ### Claim 15 (depends on 11) The network node of claim 11, wherein the processor is further configured to: send, after an expiration of the timer, another packet to the second node, wherein the another packet includes a status field that indicates that the operational session is inactive. ### Claim 16 (depends on 11) The network node of claim 11, wherein the processor is further configured to: drop the packet in response to determining that the first identifier is different from the My Discriminator value of the another network node; and drop the packet in response to determining that the first IP address included in the packet is different from the second IP address of the another network node. ### Claim 17 (depends on 11) The network node of claim 11, wherein the network node and the another network node are configured to operate in a Protocol Independent Multicast Sparse Mode (PIM-SM). ### Claim 18 (depends on 11) The network node of claim 11, wherein the operational session is a Bidirectional Forwarding Detection (BFD) session. ### Claim 19 (depends on 11) The network node of claim 11, wherein the another network node includes a Designated Router (DR) or a Backup Designated Router (BDR). ### Claim 20 (depends on 11) The network node of claim 11, wherein a value for the timer is determined without a performance of a negotiation with the another network node.