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Network Architecture

USDN (User-defined Software Defined Network) implements a distributed network architecture that enables secure, scalable connectivity between nodes and clients across different network environments.

Overview​

The USDN network architecture consists of several key components working together to provide seamless connectivity:

  • Controller: Central management component that coordinates network operations
  • Nodes: Distributed network endpoints that handle traffic routing and forwarding
  • Clients: End-user devices that connect to the USDN network
  • Internet Gateway: Provides external connectivity and routing to public networks

Network Topology​

The following diagram illustrates the simplified USDN network architecture:

Key Components​

Controller​

The controller serves as the central coordination point for the USDN network. It:

  • Manages peer-to-peer connections using blockchain
  • Coordinates network configuration across all nodes
  • Handles routing decisions and policy enforcement
  • Provides connectivity to external networks including Google servers

Network Nodes​

Each node in the USDN network contains several components:

  • gPRC/P2P Connections via Wireguard: Secure tunneling for encrypted communications
  • Docker Bridge: Container networking for isolated services
  • LCP (Link Control Protocol): Manages link-layer communications
  • VRF (Virtual Routing and Forwarding): Provides network isolation and routing
  • VPP (Vector Packet Processing): High-performance packet processing
  • NAT44: Network Address Translation for IPv4 traffic

Client Connectivity​

Clients connect to the USDN network through:

  • Direct connection to node LAN interfaces
  • IP addressing from dedicated subnets (e.g., 10.0.1.100/24, 10.0.2.200/24)
  • Linux kernel-based networking stack

Inter-Node Communication​

Nodes communicate with each other through:

  • L2 switching infrastructure
  • WAN interfaces for external connectivity
  • Secure tunneling protocols for data protection

Inter-Node Communication Details​

The USDN network utilizes a blockchain-based peer-to-peer communication system for secure data transport between the controller and nodes. The following diagram illustrates this detailed communication flow:

Communication Flow Process​

  1. Controller Initiation: The controller creates encrypted transactions containing network configuration and routing information
  2. Blockchain Transport: Transactions are distributed through the blockchain network to target nodes using peer-to-peer protocols
  3. Connection Verification: All connections are verified and authenticated by the controller before data transmission
  4. vrouter-agent Processing:
    • Receives encrypted blockchain transactions
    • Decrypts the transaction data
    • Processes and validates the network commands
  5. vrouter Execution:
    • Receives decrypted API commands from vrouter-agent
    • Acts as VPP API client processor
    • Translates commands into VPP-compatible configurations
  6. VPP Data Plane: Executes the actual packet processing and routing based on configurations from vrouter

Security Features​

  • End-to-End Encryption: All data is encrypted before blockchain transmission
  • Blockchain Integrity: Transaction immutability ensures data integrity
  • Connection Verification: Multi-layer authentication prevents unauthorized access
  • Component Isolation: Each component (agent, router, VPP) operates in isolated contexts

Traffic Flow​

  1. Client-to-Internet: Client traffic flows through the node's LAN interface, through VPP processing, NAT translation, and out via WAN interface
  2. Inter-Client: Traffic between clients on different nodes traverses the L2 switch infrastructure
  3. Control Plane: Management traffic flows between nodes and the controller using P2P protocols over secure channels

This architecture provides scalable, secure networking with centralized control and distributed data plane processing.