Windows 10 added Windows Update Delivery Optimization to allow devices to share and distribute feature and security updates across a network without having to rely on Windows Software Update Services (WSUS). Delivery Optimization uses peer resources to share the patches. You can also use it with Windows Update, WSUS, Windows Update for Business or System Center Configuration Manager (when installation of Express Updates is enabled).
To use Delivery Optimization, you must have machines with a minimum of Windows 10 Version 1511, Windows Server core installation minimum of 1709, internet of things (IoT) devices running a minimum 1803, and finally HoloLens devices running a minimum of 1803. The settings are located under the group policy under Computer ConfigurationPoliciesAdministrative TemplatesWindows ComponentsDelivery Optimization. In Mobile Device Management, the same settings are under Vendor/MSFT/Policy/Config/DeliveryOptimization/.
Because Windows updates are digitally signed, you can get bits of updates and the update will be recompiled from the parts, verified to the hash values, and be secure to then install on systems. Thus, you can use your own network resources to distribute updates. The basic process is for the client to check for updates.