When you set up content caching on your Mac, cacheable content is downloaded once from Apple to the Mac, then cached for delivery to connected Mac computers and iOS devices on the network, saving Internet data.
Tethered caching is a feature of content caching that allows iOS devices connected via USB to share the Mac's Internet connection and content cache. This can save time, local Wi-Fi, and bandwidth when using a cart or USB hub and updating several devices at once, compared to each device updating individually over Wi-Fi.
Set up content caching and tethered caching
- Choose Apple () menu > System Preferences, then click Sharing.
- From the list of services, select Content Caching.
- To turn on tethered caching, select the Internet Connection checkbox. Additonal requirements for tethered caching:
- Personal Hotspot must be turned off on the connected iOS device.
- Your Mac must be connected to the Internet using Ethernet.
- Your Mac should be plugged into AC power, because tethered caching prevents your Mac from sleeping.
- The tethered iOS device must be using iOS 10.3 or later.
- Press and hold the Option key to show the Advanced Options button, then click Advanced Options. In Advanced Options you can set up clients, peers, or parents.
For example, if you have a district office, you can make an iMac your parent for the caching service. Locations throughout the city could use the district office as their parent caching service, allowing potential updates to flow from the district office to each location. But a parent caching service shouldn't cache iCloud content: each location should cache their own iCloud content.
For more information, see Manage content caching on Mac.