gPTP Time Synchronization Test: Packet Transmission Delay

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gPTP Time Synchronization Test: Packet Transmission Delay

370 次查看
zyz
Contributor III

Recently, during our GPTP time synchronization testing, we observed a delay issue with Follow_Up/Sync messages (based on the receiver's captured data):

  • A message that should have been received at 53 seconds was actually received at 54 seconds, and the Follow_Up message carried a timestamp of 53 seconds.

  • A message that should have been received at 54 seconds was actually received at 55 seconds, and the Follow_Up message carried a timestamp of 54 seconds.
    Please refer to the attachment for detailed information.

Could you help analyze the possible causes of this issue? Additionally, I have a question: In the GPTP protocol, is T1 recorded at the exact moment when the Sync message leaves the MAC layer and enters the PHY layer, or is it recorded when the Sync message is placed into the MAC internal transmit buffer?
If T1 is recorded when the Sync message leaves the MAC layer and enters the PHY layer, does this mean the issue is unrelated to the Master device?

 

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362 次查看
chenyin_h
NXP Employee
NXP Employee

Hello, @zyz 

Thanks for the post.

Let's discuss it together in your alternative thread.

 

BR

Chenyin

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