How to Configure Delivery Optimisation, Peer-to-Peer Caching, and Bandwidth Limits in Windows 11

Architectural Foundation of Delivery Optimisation and P2P Content Distribution

Deploying multi-gigabyte operating system feature updates, cumulative patches, and enterprise applications across hundreds of Windows 11 endpoints can easily saturate local internet gateway connections. To eliminate redundant external bandwidth consumption, Microsoft engineered Delivery Optimisation (DO), a cloud-coordinated, peer-to-peer (P2P) content distribution subsystem managed by the Windows service DoSvc.

When an endpoint initiates a download for Windows Updates, Microsoft Store applications, or Microsoft Intune Win32 packages, Delivery Optimisation contacts the cloud-based DO metadata service. Rather than downloading the entire binary payload directly from Microsoft content delivery networks (CDNs), the service breaks the payload into cryptographic 1 MB chunks, each validated by a SHA-256 hash. The cloud service returns a swarm manifest identifying neighbouring Windows 11 peers on the local subnet or corporate boundary that already possess those chunks. The local machine retrieves chunks in parallel from nearby peers over TCP/UDP port 7680, sourcing only missing or un-cached blocks from the external Microsoft CDN.

Download Mode (DODownloadMode)	Peering Boundary Scope	Cloud Coordination	Network Protocol	Recommended Environment
0 (HTTP Only)	None (Peering disabled)	None	Direct HTTPS to CDN	Isolated lab or metered test rigs
1 (LAN / Subnet)	Same local broadcast subnet (NAT)	Delivery Optimisation Cloud	TCP/UDP Port 7680	Home offices, small branch offices
2 (Group / Domain)	Active Directory Site or custom Group ID	Delivery Optimisation Cloud	TCP/UDP Port 7680	Enterprise campus LANs across multiple VLANs
3 (Internet)	Peers across the public internet	Delivery Optimisation Cloud	TCP/UDP Port 7680	Public peer-to-peer consumer mesh
99 (Simple Mode)	Connected Cache Server only	Bypasses DO cloud service	Direct HTTP/HTTPS	Air-gapped secure networks with local cache

Configuring Delivery Optimisation in Windows 11 Settings

End users and network administrators can tune bandwidth ceilings and peer-sharing scopes directly through the Windows 11 graphical interface.

Step 1: Configure Peer Sharing Scope

1. Press Win + I to launch Settings.
2. In the left-hand navigation pane, select Windows Update.
3. Click Advanced options, then scroll down and select Delivery Optimisation.
4. Ensure the master toggle labelled Allow downloads from other PCs is set to On.
5. Select your peering boundary:
   • Devices on my local network: Restricts P2P traffic strictly to machines sharing your local router and subnet (Recommended for home networks).
   • Devices on the internet and my local network: Allows seeding and receiving chunks across public internet swarms.

Step 2: Enforce Granular Bandwidth Throttling

1. Inside the Delivery Optimisation panel, click Advanced options.
2. Under Download settings, select Absolute bandwidth or Percentage of measured bandwidth:
   • Limit how much bandwidth is used for downloading updates in the background: Set a conservative percentage (e.g., 25%) to prevent patch downloads from interfering with business-critical VoIP or database calls.
   • Limit how much bandwidth is used for downloading updates in the foreground: Regulates user-initiated manual updates (e.g., 60%).
3. Under Upload settings:
   • Check Limit how much bandwidth is used for uploading updates to other PCs on the internet (e.g., 30%).
   • Set a Monthly upload limit (e.g., 250 GB) to prevent exceeding ISP upstream data allowances.

Enterprise Policy Management via PowerShell and Registry

Enterprise administrators configure Delivery Optimisation fleet-wide using Group Policy, Microsoft Intune, or PowerShell scripts:

# 1. Query real-time Delivery Optimisation cache and peer status
Get-DeliveryOptimizationStatus

# 2. Inspect aggregate bandwidth savings from local peers versus CDN
Get-DeliveryOptimizationPerfSnap | Select-Object -Property `
    BytesFromPeers, BytesFromHttp, PercentPeerCaching, TotalBytesDownloaded

# 3. Configure Group Peering Mode (Mode 2) via Registry
New-Item -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" -Force
Set-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" `
    -Name "DODownloadMode" -Value 2 -PropertyType DWord

# 4. Assign a custom Enterprise Group ID (GUID) to unify devices across VLAN boundaries
Set-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization" `
    -Name "DOGroupId" -Value "{a1b2c3d4-e5f6-7890-abcd-ef1234567890}" -PropertyType String

# 5. Clear local Delivery Optimisation cache files
Delete-DeliveryOptimizationCache

Auditing Bandwidth Offload via Activity Monitor

To verify the efficiency of peer caching across your local fleet, inspect the built-in telemetry dashboard:

1. Navigate back to Settings > Windows Update > Advanced options > Delivery Optimisation.
2. Click Activity monitor.
3. Examine the telemetry visualisers:
   • Download Statistics: Displays the proportion of data sourced from Microsoft (HTTP) versus PCs on your local network. In well-tuned enterprise environments, local network peer sharing routinely achieves 70% to 90% bandwidth offload.
   • Upload Statistics: Displays total gigabytes seeded to neighbouring workstations across the local network.

Troubleshooting Delivery Optimisation and P2P Failures

Observed Anomaly	Underlying Root Cause	Technical Diagnostic Method	Remediation Protocol
Zero Peer Bytes Downloaded (0% Peering)	Outbound or inbound TCP/UDP port 7680 blocked by Windows Defender Firewall or hardware router	Run PowerShell: Test-NetConnection -ComputerName [PeerIP] -Port 7680	Open TCP/UDP 7680 across local subnets in Windows Defender Firewall rules
Peers on Different Subnets Cannot Discover Each Other	Download Mode set to 1 (LAN), which restricts discovery to the same broadcast domain	Check Get-DeliveryOptimizationStatus; no peers detected across VLAN trunk	Switch DODownloadMode to 2 (Group Mode) and assign an identical DOGroupId GUID
Device Refuses to Seed / Upload to Other PCs	Endpoint running on battery power, or free disk space fallen below minimum threshold	Inspect battery state and remaining storage capacity on system drive (C:)	Connect to AC mains power; ensure at least 32 GB free disk space remains for cache pooling
High Internet Bandwidth Usage on Metered Connections	Windows metered connection settings overridden or Delivery Optimisation set to Mode 3	Check Settings > Network & internet > Wi-Fi > Metered connection	Enable “Metered connection” toggle; Windows automatically halts all DO peer uploads on metered links