Time Synchronization in Embedded Systems, overview of gPTP (Precision Time Protocol)

[@IntrepidControlSystems]

Presentation slides are located at cdn.intrepidcs.net/events/Webinars/Time_Sync_Embedded_Systems_gPTP_20210125.pdf

[@connieliu9403]

WOW, great video! explain the complex gPTP in such an easy-understanding way!

[@KinzRulz]

There are 2 types of switches 1. Cut through 2. Store and Forward So Residence time would depend on type of switch. So both switches have the intelligence to calculate and update this in correction factor field of gPTP follow up message?

[@coltcorrea3075]

Yes residence time does depend on a variety of factors for sure. Any switch that supports gPTP must support updating the correction factor field. Modern switches have the ability to make modifications to the packets at wire speed. Therefore gPTP support with cut-through mode is possible. The data sheet of the specific switch should tell you the details if this is supported or not. Not all switches support gPTP and not all switches support cut-through mode but there is nothing in modern switch technology that will prevent cut-through mode with gPTP support.

[@אלון-מ4ו]

In the second section ============================== A rate of 500 Kbps => 1 bit every 2 usec Sending 8 Bytes meaning 8x8 = 64 bits => 128 usec So, why it is written in the slide 256 usec? ------------------------------------------------------------- A rate of 100 Mbps => 1 bit every 10 nsec Sending 1500 Bytes meaning 1500x8 = 12,000 bits => 120 usec So, why it is written in the slide 111 usec?

[@mcdivyakanth]

You have to also consider overheads involved for e.g. in case of CAN, irrespective of payload be it 1 byte or 8 bytes, there are additional data such as CANID, Type of Frame, DLC, CRC, Acknowledge etc. And, same with Ethernet.