Heartbeat Direction and Acknowledgement

We have a Java client server application with a custom protocol using TCP/IP. We have found it necessary to use a heartbeat within the protocol due to dead socket connection issues.

We have had the heartbeat since the beginning going from client to server with the server responding with an acknowledgment.

We have recently had a timeout issues with the clients, and after analysing the code have come up with a couple of questions I am unsure about.

1 - What direction is best for a heartbeat, I think we chose 'client to server' as it takes the load of the server. I was thinking of changing it to 'server 开发者_运维百科to client' however we have control of both the client and server code, so we don't need worry so much about time wasting clients.

2 - Is it necessary to acknowledge heartbeats to prove the connection is alive in both directions?

Many thanks

I'm thinking any traffic in either direction should be enough to keep it alive but it doesn't hurt to respond with a "ping" with a "pong". Traditionally the client sends the heartbeat and the server will be responsible to shutting down unresponsive clients so what you have sounds right.

have you tried setting the timeout to zero? Could it be network devices that are interfering with your socket connection timeout?

try {
  ServerSocket server = new ServerSocket(2048);
  server.setSoTimeout(0); // never time out
  try {
    Socket s = server.accept(  );
    // handle the connection
    // ...
  }
  catch (InterruptedIOException e) {
    System.err.println("No connection within 30 seconds");
  }
  finally {
    server.close(  );
  }
catch (IOException e) {
  System.err.println("Unexpected IOException: " + e);
}