# US 12,003,397 B2 · Delay measurement device, delay measurement method, and delay measurement program > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,397 B2 - Document ID: US12003397B2 - Status: Granted - Kind: B2 - Application number: 18/022,699 - Filed: 2020-08-24 - Published: 2023-10-05 - Granted: 2024-06-04 - Earliest claimed: 2020-08-24 - Assignees: Nippon Telegraph and Telephone Corporation - Applicants: Nippon Telegraph and Telephone Corporation - Inventors: Satoshi Nakatsukasa; Toshihiro Yokoi; Ken Takahashi - Web page: https://patentgrep.com/patent/US12003397B2 ## CPC - H04L 41/5009: Determining service level performance parameters or violations of service level contracts, e.g. violations of agreed response time or mean time between failures [MTBF] - H04L 43/0858: {One way delays} - H04L 43/10: Active monitoring, e.g. heartbeat, ping or trace-route - H04L 45/26: {Route discovery packet} - H04L 45/302: Route determination based on requested QoS - H04L 43/0864: Round trip delays - H04L 43/087: Jitter - H04L 47/283: in response to processing delays, e.g. caused by jitter or round trip time [RTT] - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A delay measurement device measures a delay time of an end-to-end route path of a virtual private network related to a predetermined user. The delay measurement device includes a measurement route generation unit configured to generate a first route that transfers to a start point node of a route path, transfers back on the route path, and then returns to itself, and to generate a second route of a route that transfers to the start point node of the route path and returns to itself; a packet transmission/reception unit configured to transmit and receive packets circulating on the first route; a delay measurement unit configured to measure a time from transmission of the packet to reception of the packet to set the measured time as a delay time of the route; and a one-way delay calculation unit configured to calculate a one-way delay time of the route path. ## Claims ### Claim 1 A delay measurement device for measuring a delay time of an end-to-end route path of a virtual private network related to a predetermined user, the device comprising a storage medium storing instructions and a computer configured to execute the instructions to perform operations comprising: generating a first route that transfers to a start point node of a route path, transfers back on the route path, and then returns to the delay measurement device; transmitting and receiving a first packet circulating on the first route; measuring a time from transmission of the first packet to reception of the first packet to set the measured time as a delay time of the first route; generating a second route of a route that transfers to the start point node of the route path and returns to the delay measurement device; transmitting and receiving a second packet circulating on the second route; measuring a time from transmission of the second packet to reception of the second packet to set the measured time as a delay time of the second route; and calculating a one-way delay time of the route path by subtracting a delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 2 (depends on 1) The delay measurement device according to claim 1, wherein calculating the one-way delay time of the route path comprises: adding a correction delay value to the value obtained by subtracting the delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 3 (depends on 1) The delay measurement device according to claim 1, wherein the operations further comprise: specifying a direction of delay variation when the calculated one-way delay time varies. ### Claim 4 (depends on 3) The delay measurement device according to claim 3, wherein the operations further comprise: generating a third route that transfers to the start point node of the route path, transfers in one direction on the route path, and then returns to itself; generating a fourth route that transfers to an end point node of the route path, transfers in one direction on the route path, and then returns to itself; and specifying the direction of delay variation by comparing a delay time of the third route with a delay time of the fourth route. ### Claim 5 (depends on 1) The delay measurement device according to claim 1, Wherein the operations further comprise: recording and generating route information in which node identifiers of the first and second routes are arranged in packets transmitted to a communication network configured by connecting a plurality of nodes to each other; and clocking a time. ### Claim 6 (depends on 5) The delay measurement device according to claim 5, wherein the plurality of nodes are configured to sequentially transfer the packets to nodes corresponding to the node identifiers included in the route information. ### Claim 7 A delay measurement method comprising: generating a first route that transfers to a start point node of a route path from a delay measurement device, transfers back on the route path, and then returns to the delay measurement device; transmitting and receiving a first packet circulating on the first route; measuring a time from transmission of the first packet to reception of the first packet to set the measured time as a delay time of the first route; generating a second route of a route that transfers to the start point node of the route path and returns to the delay measurement device; transmitting and receiving a second packet circulating on the second route; measuring a time from transmission of the second packet to reception of the second packet to set the measured time as a delay time of the second route; and calculating a one-way delay time of the route path by subtracting the delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 8 (depends on 7) The delay measurement method of claim 7, wherein calculating the one-way delay time of the route path comprises: adding a correction delay value to the value obtained by subtracting the delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 9 (depends on 7) The delay measurement method of claim 7, further comprising: specifying a direction of delay variation when the calculated one-way delay time varies. ### Claim 10 (depends on 9) The delay measurement method of claim 9, further comprising: generating a third route that transfers to the start point node of the route path, transfers in one direction on the route path, and then returns to itself; generating a fourth route that transfers to an end point node of the route path, transfers in one direction on the route path, and then returns to itself; and specifying the direction of delay variation by comparing a delay time of the third route with a delay time of the fourth route. ### Claim 11 (depends on 7) The delay measurement method of claim 7, further comprising: recording and generating route information in which node identifiers of the first and second routes are arranged in packets transmitted to a communication network configured by connecting a plurality of nodes to each other; and clocking a time. ### Claim 12 (depends on 11) The delay measurement method of claim 11, wherein the plurality of nodes sequentially transfer the packets to nodes corresponding to the node identifiers included in the route information. ### Claim 13 A non-transitory computer-readable medium storing delay measurement program for causing a computer to execute operations comprising: generating a first route that transfers to a start point node of a route path, transfers back on the route path, and then returns to itself; transmitting and receiving a first packet circulating on the first route; measuring a time from transmission of the first packet to reception of the first packet to set the measured time as a delay time of the first route; generating a second route that transfers to the start point node of the route path and returns to itself; transmitting and receiving a second packet circulating on the second route; measuring a time from transmission of the second packet to reception of the second packet to set the measured time as a delay time of the second route; and calculating a one-way delay time of the route path by subtracting the delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 14 (depends on 13) The non-transitory computer-readable medium of claim 13, wherein calculating the one-way delay time of the route path comprises: adding a correction delay value to the value obtained by subtracting the delay time of the second route from the delay time of the first route and dividing the difference by 2. ### Claim 15 (depends on 13) The non-transitory computer-readable medium of claim 13, wherein the operations further comprise: specifying a direction of delay variation when the calculated one-way delay time varies. ### Claim 16 (depends on 15) The non-transitory computer-readable medium of claim 15, wherein the operations further comprise generating a third route that transfers to the start point node of the route path, transfers in one direction on the route path, and then returns to itself; generating a fourth route that transfers to an end point node of the route path, transfers in one direction on the route path, and then returns to itself; and specifying the direction of delay variation by comparing a delay time of the third route with a delay time of the fourth route. ### Claim 17 (depends on 13) The non-transitory computer-readable medium of claim 13, wherein the operations further comprise recording and generating route information in which node identifiers of the first and second routes are arranged in packets transmitted to a communication network configured by connecting a plurality of nodes to each other; and clocking a time. ### Claim 18 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the plurality of nodes sequentially transfer the packets to nodes corresponding to the node identifiers included in the route information.