# US 11,115,319 B2 · Using BFD packets in a network tunnel environment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,319 B2 - Document ID: US11115319B2 - Status: Granted - Kind: B2 - Application number: 16/519,703 - Filed: 2019-07-23 - Published: 2021-01-28 - Granted: 2021-09-07 - Earliest claimed: 2019-07-23 - Assignees: Hewlett Packard Enterprise Development LP - Applicants: Hewlett Packard Enterprise Development LP - Inventors: David Corrales Lopez; Johan Martin Oviedo Paniagua; Daniel Canessa Valverde - Web page: https://patentgrep.com/patent/US11115319B2 ## CPC - H04L 45/28: using route fault recovery - H04L 12/4633: {Interconnection of networks using encapsulation techniques, e.g. tunneling} - H04L 45/20: {Hop count for routing purposes, e.g. TTL} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Examples disclosed herein relate to a method comprising receiving requesting, at a first network device, a Bidirectional Forwarding Detection session with a second network device, determining, by the first network device, that the BFD session is for single hop data and determining, by the first network device, that the BFD session is over a network tunnel from the first network device to the second network device. The method may include initiating the BFD session between the first and second network devices, wherein the BFD session is shared between multiple clients requesting BFD sessions on a network tunnel, but is not shared not between tunneled and non-tunneled sessions between the multiple clients. The method may include transmitting, the single hop data to the second network device via the network tunnel, wherein the network tunnel traverses a multiple hop network path and disabling echo packets for the BFD session. ## Claims ### Claim 1 A method comprising: requesting, at a first network device, a Bidirectional Forwarding Detection (BFD) session with a second network device, wherein the BFD session has a corresponding BFD session key; determining, by the first network device, that the BFD session is for single hop data; determining, by the first network device, that the BFD session is over a network tunnel from the first network device to the second network device; initiating the BFD session between the first and second network devices, wherein the BFD session is shared between multiple clients requesting BFD sessions on a network tunnel, but is not shared between tunneled and non-tunneled sessions between the multiple clients; initiating no more than one BFD session in memory for each BFD session key whenever multiple protocols are monitoring a same layer 3 network path; transmitting, the single hop data to the second network device via the network tunnel, wherein the network tunnel traverses a multiple hop network path; and disabling echo packets for the BFD session. ### Claim 2 (depends on 1) The method of claim 1, wherein the first network device is part of a first physical Local Area Network (LAN), the second network device is part of a second physical Local Area Network (LAN) and the a portion of the multiple hop path does not belong to either of the first physical LAN or the second physical LAN. ### Claim 3 (depends on 1) The method of claim 1, wherein the network tunnel is over one of a layer 2 tunnel or a layer 3 tunnel. ### Claim 4 (depends on 1) The method of claim 1, comprising: enforcing single hop semantics across multiple hop domains. ### Claim 5 (depends on 1) The method of claim 1 comprising: transmitting a next hop resolution result between the BFD session and a non-tunneled BFD session, the next hope resolution result defining a next hop and an outgoing interface on a network path between the first and second network devices. ### Claim 6 (depends on 1) The method of claim 1 comprising: transmitting a data packet from the first network device to the second network device over the BFD session to determine that the network tunnel is active. ### Claim 7 A non-transitory computer-readable storage medium encoded with instructions, the instructions executable by a processor of a system to cause the system to: request, at a first network device, a Bidirectional Forwarding Detection (BFD) session with a second network device, wherein the BFD session has a corresponding BFD session key; determine, by the first network device, that the BFD session is for single hop data; determine, by the first network device, that the BFD session is over a network tunnel from the first network device to the second network device; initiate the BFD session between the first and second network devices, wherein the BFD session is shared between multiple clients requesting BFD sessions on a network tunnel, but is not shared between tunneled and non-tunneled sessions between the multiple clients; initiate no more than one BFD session in memory for each BFD session key whenever multiple protocols are monitoring a same layer 3 network path, wherein the BFD session has a corresponding BFD session key; transmit, the single hop data to the second network device via the network tunnel, wherein the network tunnel traverses a multiple hop network path; and disable echo packets for the BFD session. ### Claim 8 (depends on 7) The non-transitory computer-readable storage medium of claim 7, wherein the first network device is part of a first physical Local Area Network (LAN), the second network device is part of a second physical Local Area Network (LAN) and the a portion of the multiple hop path does not belong to either of the first physical LAN or the second physical LAN. ### Claim 9 (depends on 7) The non-transitory computer-readable storage medium of claim 7, wherein the instructions executable by the processor cause the system to: enforce single hop semantics across multiple hop domains. ### Claim 10 (depends on 7) The non-transitory computer-readable storage medium of claim 7, wherein the instructions executable by the processor cause the system to: transmit a next hop resolution result between the BFD session and a non-tunneled BFD session, the next hope resolution result defining a next hop and an outgoing interface on a network path between the first and second network devices. ### Claim 11 (depends on 7) The non-transitory computer-readable storage medium of claim 7, wherein the instructions executable by the processor cause the system to: transmit a data packet from the first network device to the second network device over the BFD session to determine that the network tunnel is active. ### Claim 12 A system comprising: a session requestor to request, at a first network device, a Bidirectional Forwarding Detection (BFD) session with a second network device, wherein the BFD session has a corresponding BFD session key; a session determiner to determine, by the first network device, that the BFD session is for single hop data; a tunnel determiner to determine, by the first network device, that the BFD session is over a network tunnel from the first network device to the second network device; a session initiator to: initiate the BFD session between the first and second network devices, wherein the BFD session is shared between multiple clients requesting BFD sessions on a network tunnel, but is not shared between tunneled and non-tunneled sessions between the multiple clients and initiate no more than one BFD session in memory for each BFD session key whenever multiple protocols are monitoring a same layer 3 network path; a data transmitter to transmit, the single hop data to the second network device via the network tunnel, wherein the network tunnel traverses a multiple hop network path; and an echo disabler to disable echo packets for the BFD session. ### Claim 13 (depends on 12) The system of claim 12, wherein the first network device is part of a first physical Local Area Network (LAN), the second network device is part of a second physical Local Area Network (LAN) and the a portion of the multiple hop path does not belong to either of the first physical LAN or the second physical LAN. ### Claim 14 (depends on 12) The system of claim 12 comprising: a domain enforcer to enforce single hop semantics across multiple hop domains. ### Claim 15 (depends on 12) The system of claim 12 comprising: the data transmitter to transmit a next hop resolution result between the BFD session and a non-tunneled BFD session, the next hope resolution result defining a next hop and an outgoing interface on a network path between the first and second network devices. ### Claim 16 (depends on 12) The system of claim 12 comprising: the data transmitter to transmit a data packet from the first network device to the second network device over the BFD session to determine that the network tunnel is active. ### Claim 17 (depends on 12) The system of claim 12, wherein the network tunnel is over one of a layer 2 tunnel or a layer 3 tunnel.