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I am trying to connect my Mac to a USB-cable and a WiFi at the same time. Will this make my network faster and more stable? Or will it just only pick one network to use?

network

AGamePlayer
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  • What is the USB cable connected to? Is this a network connection over USB? – benwiggy Jan 02 '20 at 07:49
  • @benwiggy a totally different network – AGamePlayer Jan 02 '20 at 07:49
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    Does this answer your question? [How does the Mac choose which connection to use when both Wifi and Ethernet are connected?](https://apple.stackexchange.com/questions/98815/how-does-the-mac-choose-which-connection-to-use-when-both-wifi-and-ethernet-are) – anki Jan 02 '20 at 08:01
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    These are also worth reading: https://apple.stackexchange.com/questions/linked/98815/ this specifically https://apple.stackexchange.com/q/370017/313842 – anki Jan 02 '20 at 08:02

2 Answers2

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MacOS can have multiple network connections, via WiFi, Ethernet, Thunderbolt and indeed USB.

Normally, one network takes preference over another: if the protocol can't be established on one network, it will look at another. In this way, it's possible to have Internet, file sharing, and other network devices like printers all on separate connections and networks.

Your internet connection will come from only one network. You can't combine two separate network connections and use both simultaneously.

benwiggy
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I am trying to connect my Mac to a USB-cable and a WiFi at the same time.

This is called link aggregation or simply bonding. There is a very similar question in which I answer this question - Do LAN transfers use both Ethernet and WiFi by default?

In short, no, because you need a smart switch that's capable of handling that function and USB and WiFi are unable to be bonded.


Or will it just only pick one network to use?

It will pick the network that will route your traffic based on destination (there's actually another component - "cost" - but it's for another topic because it's more for routing tables in switches, routers, and gateways).

The "destination" is easy - it's the network you're trying to get to. For example, you could have multiple network adapters connected to 3 different networks at once. Let's use 3 for this example case:

  • Ethernet → 192.168.1.0 (Default)
  • WiFi → 10.0.0.0
  • USB → 172.16.0.0

If you wanted get to a printer with an IP address of 172.16.0.53, your computer would send that traffic through your USB connection. If you wanted to get to a file server (maybe you're at work) with an IP address of 10.0.0.103, it would route the traffic through WiFi. Then, if you wanted "remote control" your friends Mac that had an IP of 192.168.1.203, your traffic would go through the Ethernet adapter.

Now, if you notice, the Ethernet was designated as the "default" (any adapter can be the default, I just picked this one). This means that any traffic going to a network that your computer doesn't know about will go through this interface. So, the Internet being a massive collection of what seems countless public networks, anything going there (like to http://apple.com with IP address of 17.142.160.59), that traffic will be routed through that interface.

The "priority" only comes into play when you have two (or more) adapters connected to the same network(s) like your Ethernet and WiFi both connecting to the 192.168.0.0 network. Normally, the priority will be the one with the lowest latency (quickest to respond, not necessarily the fastest data rate) unless you specify which one should take priority.

Allan
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