DP83TC811EVM: Packet Loss

My customer is testing the DP83TC811EVM but they’re experiencing the packet loss detailed in their message below. Any ideas what could be causing this?:

Are you able to find out whether the designer of the DP83TC811EVM board noticed any packet loss while testing? I’m currently testing our media converter using TI’s converter connected back-to-back (computer 1 <-> Our converter <-> TI converter <-> computer 2) and I’m getting around 4 % loss going from computer 1 to computer 2, and around 1.2 % loss going from computer 2 to computer 1, and I’m having some trouble figuring out what’s causing the loss. The converter uses the same automotive ethernet PHY, but a different ethernet PHY, with the MII signals connected in back-to-back mode. Let me know what you find out.

Here are more details about the PHYs used for the test for your reference:

I’m using the DP83TC811S-Q1 automotive ethernet PHY, which is what is being used in the TI evaluation board, but the ethernet PHY I’m using is a KSZ8081MNXIA from Microchip whereas the evaluation board uses TI’s DP83822 PHY. I did not think that using a different ethernet PHY would have made a difference since they both do the same thing. I have the two PHYs connected in MII back-to-back mode, so MII TX pins of PHY 1 -> RX pins of PHY 2 and TX pins of PHY 2 -> RX pins of PHY 1. I set our board’s automotive ethernet PHY to master, and set the evaluation board’s PHY to slave. Let me know if you need any more information.

Thanks,

Antonio