P2P Connection Failure

P2P Connection Conditions Explanation

Local Screen Mirroring (Within Same Local Network)

• Local Network IPv4 ⇆ Local Network IPv4
• Control end and controlled end are under the same local network, can directly establish P2P connection, no relay server needed.

Remote Screen Mirroring (Different Network Environments)

Scenarios Requiring Relay Server

Common Network Type Explanations

• ✅ Most Mobile, Unicom, Telecom SIM cards, All-network data cards, broadband and shared router networks
  • Usually have public network IPv6 addresses, can successfully establish P2P direct connections, no relay server needed, achieving remote screen mirroring and large file transfers.
• ✅ Router default not enabling public network IPv6
  • Log in to router management backend to manually enable IPv6
  • After enabling, recommended to restart router to ensure effectiveness
• ✅ Cloud phone examples supporting public network IPv6: StarChain Cloud, Mobile Cloud
• ✅ Cloud phone examples supporting public network IPv4: Mango Cloud
• ✅ Unicom users can apply for public network IPv4 addresses, Mobile and Telecom generally don't provide such services
• 🛑 Network scenarios unable to establish P2P direct connections
  • Few IoT cards, single-network data cards
  • Some cloud phones (like Tianyi Cloud, Shark Cloud)
  • These networks only have local network IPv4 addresses, lack public network IPv6 support, causing inability to directly P2P connect

Check Computer/Phone Network Information

1. Open browser to visit: http://cloud.jsdevhub.com/#/network
2. Click Collect Candidates to view IP information:
   • ✅ Has public network IPv6 → Can directly establish remote P2P connection
   • ❌ No public network IPv6 → Need to continue troubleshooting or setup relay server

P2P Connection Failure Solutions

1. Check Control End and Controlled End IP

• Check computer end and phone end network information separately
• Whether having public network IPv6 address
• If no public network IPv6, proceed to next troubleshooting step

2. Troubleshoot IP Problems

• Check router settings, ensure IPv6 function is enabled, and restart router
• If still no public network IPv6, contact broadband provider to confirm whether network supports public network IPv6

⚠️ If still cannot obtain public network IPv6 after above steps, P2P direct connection cannot be established

3. Setup Relay Server

• When public network IPv6 cannot be resolved, achieve remote screen mirroring and file transfer through setting up relay server
• Relay server serves as bridge for NAT traversal and cross-network connection, ensuring stable connection
• Reference tutorial:

Cloud Control System CentOS 8 Screen Mirroring Relay Server Installation Tutorial

Bilibili

Step-by-step demonstration of quickly deploying Cloud Control central control service Docker image on CentOS 8, achieving stable and efficient P2P intranet penetration solution for remote screen mirroring.