MacBook Air/Pro: USB Ethernet keeps disconnecting

Using a hub/adapter that supports USB PD (pass through power) permits simultaneous connection of your USB peripherals along with your Mac's Power connection. This serves two major benefits:

1) You can conveniently charge and use the Mac while connected to other devices

2) Potential issues of having sufficient available power for connected devices are eliminated

You don't necessarily have to simultaneously connect your Mac's Power Adapter, but have the opportunity to do so while removing potential issues relating to inadequate power being available. Don't forget, the hub/adapter itself needs power to operate - in addition to any other devices that may be connected to it.

When both are connected, and the Ethernet drops off, my suspicion is that the Mac's USB port is not providing enough power to the hub/adapter that you are using ... or any similar device.

What I think should solve this issue is to use a powered hub so that any peripherals attached will not "overwhelm" your Mac's USB-C port. Note that, for these devices, you do NOT need a Thunderbolt 4 or 5 hub nor cables ... unless you later decide to connect a Thunderbolt 4/5 device.

I suggest that you consider getting one. A great source for these is MacSales. You can also talk with a sales representative and they should steer you towards the appropriate hub(s) that should work best for your needs. They also have an excellent return policy. Full disclosure: I do not work for MacSales. I've only been a customer of theirs for a number of years.

Powered USB-C hubs are available in small form-factors from multiple manufacturers - many of which will be powered using your Mac's own Power Adapter via the hub's USB PD pass-through connection.

Of those available, UGREEN (a respected thitd-party manufacturer) offer multiple choices. Here are just a few that feature an Ethernet port in addition to other ports/interfaces:

https://uk.ugreen.com/collections/hubs-1

Perhaps also consider Kingston, Anker, Hyperdrive and Satechi - although there are many others from which to choose. A Google Search for USB-C Hubs compatible with Mac will find a number of articles and recommendations.

Yes ... if you go to the link I provided, you can filter on what types of ports you need.

I just did this for Ethernet, and it came up with three docks that may work for you.

Ref: https://eshop.macsales.com/shop/docks#drive-docking-stations:multi-port-dock,interface-ports:gigabit-ethernet

Typically, you would plug your Mac's power adapter into the dock and the dock will pass through this power to both your Mac and to any peripherals connected to the dock.

Again, I suggest that you speak with a MacSales Sales Agent and they should set you straight.

Did you follow the link in my initial reply? If not, start there.

Here's another link to explore:

https://us.ugreen.com/collections/usb-hub?filter.p.m.custom.fliter_value=Hubs&filter.p.m.custom.fliter_value=USB+Powered&filter.p.m.custom.fliter_value=Ethernet&filter.p.m.custom.fliter_value=macOS&filter.p.m.custom.fliter_value=Travel%2FPortable+Use&page=2

The RJ45 port would either make the whole Mac thicker, or means a bump, or a failure-prone deployable socket. The structure has to change too, as the Mac could otherwise more easily bend at a large connector piercing through the sidewalls.

Gigabit Ethernet is slower than most recent Wi-Fi, too.

More generally, wired connections are not where Apple is headed, and MacBook Air is not the best choice for requirements involving lots of directly-wired connections. MacBook Pro at least has more USB-C ports.

If you need a wired network connection and cannot use Wi-Fi 6E with 5 GHz and 6 GHz Wi-Fi, then Ubiquiti has 5 GbE and 10 GbE connections, supporting macOS 14.2 and later. This assumes the local wired network infrastructure is at least gigabit, and preferably faster.

As for some dock options: https://www.brydge.com/thunderbolt-docking-stations-for-windows-and-macbook

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