# US 11,451,459 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 11,451,459 B2 - Document ID: US11451459B2 - Status: Granted - Kind: B2 - Application number: 17/035,985 - Filed: 2020-09-29 - Published: 2021-01-28 - Granted: 2022-09-20 - Earliest claimed: 2012-07-24 - Assignees: Accedian Networks Inc. - Applicants: Accedian Networks Inc. - Inventors: Henrik Nydell - Web page: https://patentgrep.com/patent/US11451459B2 ## 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 measuring one or more performance parameter relating to a test path of a network, said test path comprising an originator and multiple reflectors comprising: generating by the originator a test protocol data unit; assigning a unique flow identifier uniquely identifying each reflector in the test path; collecting measurements of said performance parameters at each of said multiple reflectors; inserting said collected measurements and a timestamp in said test protocol data unit associated with said unique flow identifier corresponding to the reflector in which that measurement was collected; relaying by each reflector said test protocol data unit to a subsequent reflector along said test path until a last reflector in the test path is reached; transmitting by each of said reflectors said measurements of performance parameters directly back to said originator; wherein the last reflector in the test path sends the test protocol data unit to the originator for processing. ### Claim 2 (depends on 1) The method of claim 1, in which said performance parameters include delay. ### Claim 3 (depends on 1) The method of claim 1, in which said analyzing comprises computing a total two-way delay measurement of said test data protocol unit's transit along said test path from said originator to the last reflector, and back from the last reflector to said originator, based on said timestamps inserted in the test protocol data unit in both the downstream and upstream directions. ### Claim 4 (depends on 3) The method of claim 3, in which said one of said multiple reflectors retrieves a reverse address from said test protocol data unit and inserts a reverse address for said subsequent reflector along said test path, said one of said multiple reflectors utilizing said reverse address to return said test protocol data unit in the reverse direction along said test path. ### Claim 5 (depends on 1) The method of claim 1, in which each of said reflectors is configured with the addressing information of the next reflector in said test path, and said addressing information is used to relay the test protocol data unit to said next reflector. ### Claim 6 (depends on 1) The method of claim 1 in which said performance parameters are stored in a test data protocol unit that stores at least three timestamp values, and if said test data protocol unit does not store at least three timestamp values, said test data protocol unit is expanded to store at least three timestamp values. ### Claim 7 (depends on 1) The method of claim 1, in which said originator pre-fills said test data protocol unit with each reflector's addressing information corresponding to the unique flow identifier and said addressing information is used to relay the test data protocol unit to the next reflector. ### Claim 8 A system for measuring one or more performance parameter relating to a test path of a network, said test path comprising an originator and multiple reflectors comprising: a test protocol data unit generated by the originator and transmitted to a first reflector along the test path; a unique flow identifier uniquely identifying each reflector in the test path; a timestamp inserted in said test protocol data unit associated with said unique flow identifier of the reflector; a collection of measurements of said performance parameters at each of said multiple reflectors and a timestamp inserted in said test protocol data unit associated with said unique flow identifier corresponding to the reflector; said test protocol data unit is relayed by one reflector to a subsequent reflector downstream in the test path until a last reflector in the test path is reached; and the last reflector in the test path sends the test protocol data unit to the originator for processing; and wherein said each of said multiple reflectors transmit said measurements of performance parameters directly back to said originator. ### Claim 9 (depends on 8) The system of claim 8, in which said performance parameters include delay. ### Claim 10 (depends on 8) The system of claim 8, further comprising a total two-way delay measurement of said test data protocol unit's transit computed along said test path from said originator to the last reflector, and back from the last reflector to said originator, based on said timestamps inserted in the test protocol data unit in both the downstream and upstream directions. ### Claim 11 (depends on 8) The system of claim 8, in which each of said reflectors is configured with the addressing information of the next reflector in said test path, and said addressing information is used to relay the test protocol data unit to said next reflector. ### Claim 12 (depends on 8) The system of claim 8, in which said one of said multiple reflectors retrieves a reverse address from said test protocol data unit and inserts a reverse address for said subsequent reflector along said test path, said one of said multiple reflectors utilizing said reverse address to return said test protocol data unit in the reverse direction along said test path. ### Claim 13 (depends on 8) The system of claim 8, in which said performance parameters are stored in a test data protocol unit that stores at least three timestamp values, and if said test data protocol unit does not store at least three timestamp values, said test data protocol unit is expanded to store at least three timestamp values. ### Claim 14 (depends on 8) The system of claim 8, in which said originator pre-fills said test data protocol unit with each reflector's addressing information corresponding to the unique flow identifier, and said addressing information is used to relay the test data protocol unit to the next reflector.