What is the hostname for turns server?will it be chat servers address or we need to setup stun/turn server(or use default one eg: stun:stun.l.google.com:19302)

[sainath-everest]

 myPeerConnection = new RTCPeerConnection({
    iceServers: [     // Information about ICE servers - Use your own!
      {
        urls: "turn:" + myHostname,  // A TURN server
        username: "webrtc",
        credential: "turnserver"
      }
    ]
  });

myHostname refers to chat server host url or we need to setup our own turn server(or can we use default stun server eg: eg: stun:stun.l.google.com:19302 )?And if use the this same process using react-native-webrtc will it work (i need this for react-native app)?