# US 2017/0286359 A1 · Apparatuses, systems, and methods for accurately measuring packet propagation delays through usb retimers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0286359 A1 - Document ID: US20170286359A1 - Status: Published application - Kind: A1 - Application number: 15/089,531 - Filed: 2016-04-02 - Published: 2017-10-05 - Earliest claimed: 2016-04-02 - Assignees: Intel Corporation - Inventors: Steven B. McGowan - Web page: https://patentgrep.com/patent/US20170286359A1 ## CPC - G06F 13/4291: {using a clocked protocol} - G06F 13/1673: {using buffers} - G06F 13/4295: {using an embedded synchronisation} - H04L 9/3297: {involving time stamps, e.g. generation of time stamps} - G06F 13/36: for access to common bus or bus system - H04L 25/0298: {Arrangement for terminating transmission lines} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Methods and apparatuses relating to measuring propagation delays through USB retimers are described. In one embodiment, a retimer apparatus includes a receiver to receive a data block and a timestamp for the data block from an upstream device, a buffer to store the data block and the timestamp for transmittal, a controller to modify the timestamp to generate a modified timestamp that includes a time from a receipt of a first portion of the data block in the buffer until a transmittal of the first portion of the data block from the buffer, and a transmitter to transmit the data block and the modified timestamp to a downstream device. ## Claims ### Claim 1 A retimer apparatus comprising: a receiver to receive a data block and a timestamp for the data block from an upstream device; a buffer to store the data block and the timestamp for transmittal; a controller to modify the timestamp to generate a modified timestamp that includes a time from a receipt of a first portion of the data block in the buffer until a transmittal of the first portion of the data block from the buffer; and a transmitter to transmit the data block and the modified timestamp to a downstream device. ### Claim 2 (depends on 1) The retimer apparatus of claim 1, wherein the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block is tracked in a single clock domain. ### Claim 3 (depends on 1) The retimer apparatus of claim 1, wherein the modified timestamp is a modified Isochronous Timestamp Packet. ### Claim 4 (depends on 1) The retimer apparatus of claim 1, wherein the controller is to further modify the timestamp to generate the modified timestamp that includes a Link Delay Measurement for a first link between the upstream device and the retimer apparatus. ### Claim 5 (depends on 1) The retimer apparatus of claim 1, wherein the controller associates a second timestamp with the timestamp from the upstream device. ### Claim 6 (depends on 5) The retimer apparatus of claim 5, wherein the second timestamp is in a clock domain of the transmitter. ### Claim 7 (depends on 5) The retimer apparatus of claim 5, wherein the second timestamp passes through the buffer with the data block and the timestamp for the data block. ### Claim 8 (depends on 1) The retimer apparatus of claim 1, further comprising a counter to track the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block. ### Claim 9 A method comprising: receiving a data block and a timestamp for the data block from an upstream device with a receiver of a retimer apparatus; storing the data block and the timestamp for transmittal in a buffer of the retimer apparatus; modifying the timestamp to generate a modified timestamp including a time from a receipt of a first portion of the data block in the buffer until a transmittal of the first portion of the data block from the buffer; and transmitting the data block and the modified timestamp to a downstream device with a transmitter of the retimer apparatus. ### Claim 10 (depends on 9) The method of claim 9, wherein the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block is tracked in a single clock domain. ### Claim 11 (depends on 9) The method of claim 9, wherein the modified timestamp is a modified Isochronous Timestamp Packet. ### Claim 12 (depends on 9) The method of claim 9, comprising further modifying the timestamp to generate the modified timestamp including a Link Delay Measurement for a first link between the upstream device and the retimer apparatus. ### Claim 13 (depends on 9) The method of claim 9, further comprising associating a second timestamp with the timestamp from the upstream device. ### Claim 14 (depends on 13) The method of claim 13, wherein the second timestamp is in a clock domain of the transmitter. ### Claim 15 (depends on 13) The method of claim 13, further comprising passing the second timestamp through the buffer with the data block and the timestamp for the data block. ### Claim 16 (depends on 9) The method of claim 9, further comprising tracking the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block with a counter. ### Claim 17 An apparatus comprising: a hardware processor; a host; and a retimer apparatus comprising: a receiver to receive a data block and a timestamp for the data block from the host; a buffer to store the data block and the timestamp for transmittal; a controller to modify the timestamp to generate a modified timestamp that includes a time from a receipt of a first portion of the data block in the buffer until a transmittal of the first portion of the data block from the buffer; and a transmitter to transmit the data block and the modified timestamp to a downstream device. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block is tracked in a single clock domain. ### Claim 19 (depends on 17) The apparatus of claim 17, wherein the modified timestamp is a modified Isochronous Timestamp Packet. ### Claim 20 (depends on 17) The apparatus of claim 17, wherein the controller is to further modify the timestamp to generate the modified timestamp that includes a Link Delay Measurement for a first link between the host and the retimer apparatus. ### Claim 21 (depends on 17) The apparatus of claim 17, wherein the controller associates a second timestamp with the timestamp from the host. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the second timestamp is in a clock domain of the transmitter. ### Claim 23 (depends on 21) The apparatus of claim 21, wherein the second timestamp passes through the buffer with the data block and the timestamp for the data block. ### Claim 24 (depends on 17) The apparatus of claim 17, further comprising a counter to track the time from receipt of the first portion of the data block until the transmittal of the first portion of the data block.