# US 2022/0045928 A1 · Inter-autonomous system trace route message > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0045928 A1 - Document ID: US20220045928A1 - Status: Published application - Kind: A1 - Application number: 17/452,853 - Filed: 2021-10-29 - Published: 2022-02-10 - Earliest claimed: 2019-09-27 - Assignees: Juniper Networks, Inc. - Applicants: Juniper Networks, Inc. - Inventors: Reji THOMAS; Ronald BONICA - Web page: https://patentgrep.com/patent/US20220045928A1 ## CPC - H04L 45/36: {Backward learning} - H04L 43/0811: by checking connectivity - H04L 43/10: Active monitoring, e.g. heartbeat, ping or trace-route - H04L 45/34: {Source routing} - H04L 45/741: Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6 - H04L 45/745: Address table lookup; Address filtering - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A network device may receive a message. The network device may determine that the message includes return information indicating a path to an initial device that generated the message. The network device may modify the message by adding an upstream device identifier, wherein the upstream device identifier identifies a device from which the message is received. The network device may modify the message by adding an indication of whether the initial device is reachable by the network device using a segment identifier. The network device may provide the modified message to a downstream device. ## Claims ### Claim 1 A method, comprising: receiving, by a network device, a message; determining, by the network device, that the message includes return information indicating a path to an initial device that generated the message; modifying the message by adding, by the network device to the return information, an upstream device identifier, wherein the upstream device identifier identifies a device from which the message is received; modifying the message by adding, by the network device to the return information, an indication of whether the initial device is reachable by the network device using a segment identifier; and providing, by the network device, the modified message to a downstream device. ### Claim 2 (depends on 1) The method of claim 1, further comprising: receiving a return message including the return information; and forwarding the return message to the device from which the message is received based on the upstream device identifier. ### Claim 3 (depends on 2) The method of claim 2, further comprising: determining, based on the indication and prior to forwarding the return message, that the initial device is not reachable using the segment identifier, wherein forwarding the return message to the device from which the message is received is based on determining that the initial device is not reachable using the segment identifier. ### Claim 4 (depends on 1) The method of claim 1, further comprising: receiving a return message including the return information; determining, based on the indication, that the initial device is reachable by the network device using the segment identifier; and forwarding the return message to the initial device using the segment identifier based on the initial device being reachable by the network device using the segment identifier. ### Claim 5 (depends on 1) The method of claim 1, further comprising: determining a segment identifier associated with a network address of the device from which the message is received, wherein the upstream device identifier includes the segment identifier. ### Claim 6 (depends on 1) The method of claim 1, further comprising: modifying the message by adding, to the message, a network address of the network device. ### Claim 7 (depends on 1) The method of claim 1, wherein, when the initial device is reachable by the network device using the segment identifier, the method further comprises: modifying the message by adding the segment identifier to the message. ### Claim 8 (depends on 1) The method of claim 1, wherein the network device is associated with a first autonomous system and the initial device is associated with a second autonomous system different than the first autonomous system. ### Claim 9 (depends on 1) The method of claim 1, wherein the network device is associated with a first autonomous system and the downstream device is associated with a second autonomous system different than the first autonomous system. ### Claim 10 (depends on 1) The method of claim 1, wherein the determination is performed by a control plane of the network device. ### Claim 11 (depends on 10) The method of claim 10, wherein the control plane performs the determination based on a destination option included in the message. ### Claim 12 A network device, comprising: one or more memories; and one or more processors, communicatively coupled to the one or more memories, to: determine that a message includes return information indicating a path to an initial device that generated the message; modify the message by adding, to the return information, an upstream device identifier, wherein the upstream device identifier identifies a device from which the message is received; modify the message by adding, to the return information, an indication of whether the initial device is reachable by the network device using a segment identifier; provide the modified message to a downstream device; receive a return message including the return information; and selectively forward the return message to the device from which the message is received, or to the initial device, based on the indication of whether the initial device is reachable by the network device using the segment identifier. ### Claim 13 (depends on 12) The network device of claim 12, wherein the one or more processors are further to: remove at least part of the return information based on forwarding the return message to the initial device. ### Claim 14 (depends on 13) The network device of claim 13, wherein the at least part of the return information includes the upstream device identifier. ### Claim 15 (depends on 12) The network device of claim 12, wherein the message comprises at least one of a ping message or a trace route message. ### Claim 16 (depends on 12) The network device of claim 12, wherein the upstream device identifier and the indication are determined by the network device. ### Claim 17 A non-transitory computer-readable medium storing instructions, the instructions comprising: one or more instructions that, when executed by one or more processors of a network device, cause the one or more processors to: determine that a message includes return information indicating a path to an initial device that generated the message; add, to the return information, an upstream device identifier, wherein the upstream device identifier identifies a device from which the message is received; add, to the return information, an indication of whether the initial device is reachable by the network device using a segment identifier associated with the initial device; receive or generate a return message including the return information; and selectively forward the return message to the device from which the message is received, or to the initial device, based on the indication of whether the initial device is reachable by the network device using the segment identifier. ### Claim 18 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the network device is a destination device of the message. ### Claim 19 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the one or more instructions, that cause the one or more processors to add, to the return information, the upstream device identifier, cause the one or more processors to: determine the upstream device identifier based on routing information and based on a network address of the device from which the message is received, wherein the network address is included in the return information. ### Claim 20 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the segment identifier associated with the initial device and the upstream device identifier comprise Segment Routing over Internet Protocol v6 segment identifiers.