Windows Update Delivery Optimization (WUDO) is a self-organized solution for distributed caches for Windows Updates. In default mode, WUDO identifies peers as part of a WAN based on their external IP. In case of stretched out WANs with just one breakout point, this leads to a high network load and a bottleneck. To improve the handling, Microsoft Intune can be used to set WUDO to DownloadMode=2, where peers are grouped by a groupID. The ID (GUID) is set for each device using network fingerprinting and the MAC address of the default gateway and therefore creating a more localized group. RealmJoin can be used to set the groupID for each client.
The following registry key is set to define the DOGroupID:
Remember to set the Download Mode to Group via Windows Update settings in Intune:
Delivery optimization download mode:HTTP blended with peering across private group
This is effectively DownloadMode=2. Opting-out of setting the groupID via RealmJoin can be done by setting the Policies.SetNetworkOptimizationID to false.
For more on WUDO see the Microsoft WUDO documentation (DE).