Add diagrams of client & provider interactions to README

README.md

@@ -107,6 +107,99 @@ connectClient.Cancel()
 
 More security and speed can be achieved using multiple clientIds that add and balance traffic to multiple destinations based on throughput. Each clientId has a maximum lifespan to limit tracing. This is called continuous optimization and the default way to use the public market.
 
+## Systems Diagrams
+
+### Client / Provider Interaction
+
+Core logic of network code within `/connect` folder
+
+```mermaid
+sequenceDiagram
+    participant C as Client
+    participant CM as Contract Manager
+    participant RM as Route Manager
+    participant P as Provider
+
+    C->>CM: Request Contract
+    CM-->>C: Contract Details
+    C->>RM: Send Data with Contract
+    RM->>P: Data Packets
+    P-->>RM: Acknowledge Receipt
+    RM-->>C: Notify Acknowledgement
+
+    C->>RM: Request data from provider
+    RM->>P: Retrieve data for client
+    P-->>RM: Send data packets
+    RM-->>C: Deliver data to client
+```
+
+Definitions
+- Client: entity that uses the BringYour VPN network and service
+- Provider: entity that offers network services to clients, responsible for routing client traffic through their internet network (e.g. accessing sites on behalf of a client). allowing client to access web resources privately
+- Contract: specifies data transfer limits, duration, and other conditions between a client and a provider (`protocol.Contract`)
+- Contract Manager: handles the creation, negotiation, and maintenance of contracts (`connect/transfer_contract_manager.go`)
+- Route Manager: intermediary that determines the best path for data to travel based on the available routes (`connect/transfer_route_manager.go`)
+
+Notes
+- `Contract Manager` and `Route Manager` are currently initialized by the client/s in the network (`connect.NewClientWithTag`) so each client establishes its own instance of both.
+
+#### Code diagram
+
+With the above diagram, explaining the overall structure, here is deeper look with the actual function calls and classes used within `/connect`
+
+```mermaid
+sequenceDiagram
+    participant C as Client
+    participant PT as PlatformTransport
+    participant RM as RouteManager
+    participant CM as ContractManager
+    participant SB as SendBuffer
+    participant RB as ReceiveBuffer
+    participant FB as ForwardBuffer
+    participant WS as WebSocket
+    participant P as Provider
+
+    C->>PT: NewPlatformTransport(ctx, url, auth, dial, settings, RM)
+    Note over C,PT: Client initializes the transport layer to manage network communication.
+
+    PT->>WS: wsDialer.DialContext(ctx, url, nil)
+    Note over PT,WS: PlatformTransport establishes a WebSocket connection to the provider.
+
+    WS->>P: Establish WebSocket Connection
+    P->>WS: Confirm Connection
+    Note over WS,P: WebSocket connection is established and confirmed, providing a full-duplex communication channel.
+
+    PT->>RM: UpdateTransport(sendTransport, receiveTransport)
+    Note over PT,RM: PlatformTransport informs RouteManager about the new transport routes for sending and receiving data.
+
+    RM->>SB: NewSendBuffer(ctx, C, RM, CM, settings)
+    RM->>RB: NewReceiveBuffer(ctx, C, RM, CM, settings)
+    RM->>FB: NewForwardBuffer(ctx, C, RM, CM, settings)
+    Note over RM,SB: RouteManager sets up buffers to manage the flow of data packets, ensuring ordered and reliable transmission.
+
+    SB->>WS: Write(msg)
+    Note over SB,WS: SendBuffer sends a data packet through the WebSocket to the provider.
+
+    WS->>P: Send Message to Provider
+    P->>WS: Send Message to Client
+    Note over P,WS: Provider processes the data packet and may send back a response or acknowledgment.
+
+    WS->>RB: Read(msg)
+    Note over WS,RB: ReceiveBuffer reads incoming data packets from the WebSocket.
+
+    RB->>C: receive(srcId, frames, provideMode)
+    Note over RB,C: Client receives the data packet from the ReceiveBuffer, which may include decrypted VPN traffic.
+
+    C->>FB: Forward(bytes)
+    Note over C,FB: Client instructs ForwardBuffer to forward data packets, such as outbound VPN traffic.
+
+    FB->>WS: Write(bytes)
+    Note over FB,WS: ForwardBuffer sends the data packet through the WebSocket to the provider.
+
+    WS->>P: Forward Message to Provider
+    Note over WS,P: WebSocket forwards the data packet to the provider, completing the VPN data transmission cycle.
+```
+
 ## Issues
 
 Submit issues on the [issues page](https://github.com/bringyour/connect/issues).