Doing research is a passion of mine, and there are a few weekends when I don’t sneak down to the lab for a few hours to test something. This weekend was no exception, and I sought answers to how much Internet traffic 25 freshly deployed Windows 11 23H2 clients would generate by just being online for a few hours.
Background Info
When you deploy a Windows 11 23H2 machine and log in as a normal user, you will find that the operating system, by default, will start to both install additional applications and update existing native applications and components to Windows in the background. The Windows P2P technology doing these downloads is Delivery Optimization, or DO for short, a native service in Windows 10 and Windows 11 (and Windows Server 2019 and Windows Server 2022).
To speed up the testing process, I used a scheduled task to convince Windows to update its native components. This task ran at login and started a little-known WMI method (thanks, Phil Wilcock). I also configured my OS deployments to log in automatically with a user account. This was the PowerShell script that was run by the scheduled task:
$Namespace = "Root\cimv2\mdm\dmmap"
$ClassName = "MDM_EnterpriseModernAppManagement_AppManagement01"
Get-CimInstance -Namespace $Namespace -ClassName $ClassName |
Invoke-CimMethod -MethodName UpdateScanMethod
#Test 1 – Default Delivery Optimization Settings
When deploying the 25 machines with no DO configuration, just the default Windows settings, the machines generated 26 GB of download traffic from the Internet. The DO P2P Efficiency rate was 40%, which is relatively high for the default settings. While the DO P2P Efficiency rate was pretty good, the firewall handled 69K TCP Connections via its WAN interface during the four-hour test.
Note: Of the downloaded data, 3.2 GB was downloaded via BITS. This data was downloaded from Microsoft servers that do not have BranchCache enabled. This means that this BITS content (Fonts, OneDrive update, DirectXApps, and Microsoft Edge updates) is non-peerable, and each client has to download all the data from Microsoft servers.
#Test 2 – Basic Delivery Optimization Settings Configured
With a Basic DO configuration applied to the 25 machines, based on our recommendations, the machines generated only 14 GB of download traffic from the Internet. The DO P2P Efficiency rate was 66%, and the firewall handled 40K TCP Connections via its WAN interface during the four-hour test.
#Test 3 – Basic Delivery Optimization Settings and DNS-SD Configured
In supported Windows 10 and Windows 11 builds, Delivery Optimization can be configured to ask Microsoft Update servers less frequently and instead send out a local discovery for files on the subnet using the DNS-SD protocol. This improves P2P performance and the number of connections through your Internet firewall.
With DNS-SD (local discovery) enabled, for the 25 machines involved in the test, the DO P2P Efficiency rate was a whopping 89%, and the firewall handled 34K TCP Connections via its WAN interface during the four-hour test. The machines generated 11 GB of download traffic during the four-hour test.
Note: While Windows 11 is the only supported OS for enabling local discovery via MDM Policies, you can configure it for Windows 10 machines by setting the HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization\DORestrictPeerSelectionBy registry value to 2.