Executive Summary - When a laptop running macOS Catalina 10.15 or macOS Big Sur 11 attempts to use an Ethernet port controlled by a Realtek gigabit controller (such as found within the Plugable TBT3-UDZ, TBT3-UDC3, USB3-HUB3ME, or countless products from other brands that use these chips), there can be a loss of connectivity among other wired Ethernet devices on the same local network when the host laptop enters a sleep state.
On macOS 10.15 systems, this behavior can be rectified by installing an updated Ethernet driver from Realtek.
On macOS 11 systems, this behavior can be rectified by updating the host system to macOS version 11.3 released on 4/26/2021.
Additional detail - Plugable has received customer reports of unexpected behavior when using macOS Thunderbolt 3 laptops in conjunction with the Plugable TBT3-UDZ docking station, TBT3-UDC3 docking station, and USB3-HUB3ME USB 3.0 Ethernet adapter all of which have a Realtek Ethernet interface inside.
This unexpected behavior relates to cases where the Ethernet port is being used to provide network connectivity. The wired network connection will work as expected while the laptop is operating normally. However, in some instances when the laptop enters a sleep state, the result is that other wired network devices connected to the same local network may not be able to communicate. Waking the laptop from a sleep state resolves the behavior.
For those users running macOS Catalina 10.15 on their Apple Thunderbolt 3 laptops, the solution is to install an updated driver for the Ethernet adapter directly from Realtek. Should any of our customers using any of the aforementioned products running macOS 10.15 encounter this behavior, please reach out to us directly via email@example.com so we may provide detailed instructions for installing the updated driver.
For those users running macOS Big Sur 11 on their Apple Thunderbolt 3 laptops, Plugable recommends updating to the latest release of macOS version 11.3 released on April 26th, 2021.
We have updated our knowledge base article entry regarding this topic accordingly.
If any of our customers using an Apple Thunderbolt 3 system in conjunction with any of the aforementioned products encounter any Ethernet-related network issues after updating their systems to macOS 11.3 as described above, please reach out to us directly via firstname.lastname@example.org and we will be happy to help.