# US 11,909,615 B2 · Multi-hop reflector sessions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,615 B2 - Document ID: US11909615B2 - Status: Granted - Kind: B2 - Application number: 17/891,640 - Filed: 2022-08-19 - Published: 2022-12-29 - Granted: 2024-02-20 - Earliest claimed: 2012-07-24 - Assignees: Accedian Networks Inc. - Applicants: Accedian Networks Inc. - Inventors: Henrik Nydell - Web page: https://patentgrep.com/patent/US11909615B2 ## CPC - H04L 43/0864: Round trip delays - H04L 43/50: Testing arrangements - H04L 43/106: using time related information in packets, e.g. by adding timestamps - H04L 43/12: Network monitoring probes - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method for measuring and reporting performance parameters in a network having at least one originator for generating test protocol data units, and multiple reflectors for relaying the test protocol data units along successive segments of a test path in the network. The method generates the test protocol data units at the originator and transmits the test protocol data unit along a test path that includes multiple reflectors. Each reflector relays the test protocol data unit to the next reflector along the test path. Measurements of performance parameters are collected from the multiple reflectors in the test protocol data unit by inserting timestamps into the test protocol data unit at the originator and each of the reflectors to identify the departure and arrival times for each test protocol data unit at the originator and each of the reflectors in both the downstream and upstream directions along the test path. ## Claims ### Claim 1 A method for obtaining one or more performance measurements relating to a test path of a network, said test path comprising an originator device and multiple reflector devices, the method comprising: generating by the originator device a test protocol data unit; collecting performance measurements of performance parameters at each of said multiple reflector devices; inserting said performance measurements and a timestamp in said test protocol data unit with a unique identifier corresponding to a corresponding reflector device; transmitting by each of said reflector device said performance measurements directly back to said originator device; and relaying, by each reflector device, said test protocol data unit to a subsequent reflector device along said test path until a last reflector device in the test path is reached. ### Claim 2 (depends on 1) The method of claim 1, wherein which said performance measurements include delay. ### Claim 3 (depends on 1) The method of claim 1, further comprising computing a total two-way delay measurement along said test path from said originator device to the last reflector device, and back from the last reflector device to said originator device, based on timestamps inserted in the test protocol data unit. ### Claim 4 (depends on 1) The method of claim 1, in which each of said reflector devices is configured with addressing information of a next reflector device in said test path, and said addressing information is used to relay the test protocol data unit to said next reflector device. ### Claim 5 (depends on 4) The method of claim 4, in which one of said multiple reflector devices retrieves a reverse address from said test protocol data unit and inserts a reverse address for said subsequent reflector device along said test path, said one of said multiple reflector devices utilizing said reverse address to return said test protocol data unit in a reverse direction along said test path. ### Claim 6 (depends on 1) The method of claim 1, in which said originator device pre-fills said test protocol data unit with addressing information of each reflector device used to relay the test protocol data unit to a next reflector device. ### Claim 7 A system for obtaining one or more performance measurements relating to a test path of a network, said test path comprising an originator device and multiple reflectors devices, the system comprising: a test protocol data unit generated by the originator device and transmitted to a first reflector device along the test path; one or more performance measurements collected at each of said multiple reflector devices; and said test protocol data unit is relayed by one reflector device to a subsequent reflector device downstream in the test path until a last reflector device in the test path is reached; wherein each of said multiple reflector devices transmits a copy of said test protocol data unit with said one or more performance measurements and a timestamp directly back to said originator device. ### Claim 8 (depends on 7) The system of claim 7, in which said one or more performance measurements include delay. ### Claim 9 (depends on 7) The system of claim 7, further computing a total two-way delay measurement of said test protocol data unit transit along said test path from said originator device to the last reflector device, and back from the last reflector device to said originator device, based on timestamps inserted in the test protocol data unit in both downstream and upstream directions. ### Claim 10 (depends on 7) The system of claim 7, in which each of said reflector devices is configured with addressing information of a next reflector device in said test path, and said addressing information is used to relay the test protocol data unit to said next reflector device. ### Claim 11 (depends on 7) The system of claim 7, in which one of said multiple reflector devices retrieves a reverse address from said test protocol data unit and inserts a reverse address for said subsequent reflector device along said test path, said one of said multiple reflector devices utilizing said reverse address to return said test protocol data unit in a reverse direction along said test path. ### Claim 12 (depends on 7) The system of claim 7, in which said originator device pre-fills said test data unit with addressing information of each reflector device corresponding to a unique flow identifier, and said addressing information is used to relay the test protocol data unit to a next reflector device.