You can read more about the various transports that Ditto uses in Mesh Networking.
Although Ditto automatically attempts to connect to other instances on the Local Area Network (LAN), Bluetooth Low Energy (LE), and Apple Wireless Direct Link (AWDL), supplying a DittoTransportConfig does not enable this feature by default.Rather, you manually enable peer-to-peer connections using EnableAllPeerToPeer(). (See Enabling and Disabling Transports for more information.)

​
Enabling and Disabling Transports


// Create a new DittoTransportConfig()
var config = DittoTransportConfig()

//Enable all peer to peer transports
config.enableAllPeerToPeer()

//Or enable/disable each transport separately
//BluetoothLe
config.peerToPeer.bluetoothLE.isEnabled = true
//Local Area Network
config.peerToPeer.lan.isEnabled = true
//Awdl
config.peerToPeer.awdl.isEnabled = true

ditto.transportConfig = config

do {
  try ditto.startSync()
} catch (let err) {
  print(err.localizedDescription)
}

​
Configuring Additional Settings

If you need additional connection configurations for the current Ditto instance, configure it to listen for connections on a specific port and to connect to remote instances using a host (IP) and port:
1

Before calling startSync(), create a DittoTransportConfig object with the desired settings.
2

Using the ditto.SetTransportConfig API method, set the created object on your Ditto instance.
3

Call the startSync method on your Ditto instance to initiate sync with the configured settings.

​
Syncing with Big Peer

ditto = Ditto(
  identity: DittoIdentity.onlinePlayground(
    appID: "REPLACE_ME_WITH_YOUR_APP_ID",
    token: "REPLACE_ME_WITH_YOUR_PLAYGROUND_TOKEN",
    enableDittoCloudSync: false, // This is required to be set to false to use the correct URLs
    customAuthURL: URL(string: "REPLACE_ME_WITH_YOUR_AUTH_URL")
  )
)

ditto.updateTransportConfig { transportConfig in
  // Set the Ditto Websocket URL
  transportConfig.connect.webSocketURLs.insert("wss://REPLACE_ME_WITH_YOUR_WEBSOCKET_URL")
  
  // P2P sync is enabled by default across all transports. Disable those
  // if you are only using Ditto Cloud Sync.
  transportConfig.setPeerToPeer(enabled: false)  
}

// Disable DQL strict mode so that collection definitions are not required in DQL queries
try await ditto.store.execute("ALTER SYSTEM SET DQL_STRICT_MODE = false")

do {
  try ditto.startSync()
} catch {
  print(error.localizedDescription)
}

​
Connecting to Remote Small Peers

var config = DittoTransportConfig()
// Connect explicitly to a remote devices
config.connect.tcpServers.insert("135.1.5.5:12345")
config.connect.tcpServers.insert("185.1.5.5:12345")

ditto.transportConfig = config

do {
  try ditto.startSync()
} catch (let err) {
  print(err.localizedDescription)
}

​
Initializing WebSocket Connections

Ensure WebSocket connections are discoverable across peers within your local network: 
var config = DittoTransportConfig()
config.connect.webSocketURLs.insert("ws://127.0.0.1")
ditto.transportConfig = config

do {
  try ditto.startSync()
} catch (let err) {
  print(err.localizedDescription)
}

​
Listening for Connections

var config = DittoTransportConfig()

// Listen for incoming connections on port 4000
config.listen.tcp.isEnabled = true
config.listen.tcp.interfaceIP = "0.0.0.0"
config.listen.tcp.port = 4000

ditto.transportConfig = config

do {
  try ditto.startSync()
} catch (let err) {
  print(err.localizedDescription)
}

​
Combining Multiple Transports

var config = DittoTransportConfig()
// 1. Enable All Peer to Peer Connections
config.enableAllPeerToPeer()

// 2. Listen for incoming connections on port 4000
config.listen.tcp.isEnabled = true
config.listen.tcp.interfaceIP = "0.0.0.0"
config.listen.tcp.port = 4000

// 3. Connect explicitly to remote devices
config.connect.tcpServers.insert("135.1.5.5:12345")
config.connect.tcpServers.insert("185.1.5.5:12345")

ditto.transportConfig = config

do {
  try ditto.startSync()
} catch (let err) {
  print(err.localizedDescription)
}

​
Monitoring Conditions

// Setting up inside a ViewController
let ditto = Ditto(identity: DittoIdentity.onlinePlayground(appID: "REPLACE_ME_WITH_YOUR_APP_ID", token: "REPLACE_ME_WITH_YOUR_PLAYGROUND_TOKEN"))
ditto.delegate = self
try! ditto.startSync()

// Now you can observe real time changes to the transport conditions:
extension ViewController: DittoDelegate {
   func transportConditionDidChange(transportID: Int64, condition: TransportCondition) {
       if condition == .BleDisabled {
           print("BLE disabled")
       } else if condition == .NoBleCentralPermission {
           print("Permission missing for BLE")
       } else if condition == .NoBlePeripheralPermission {
           print("Permission missing for BLE")
       }
   }
}