Why Californium wait after 65535 records while sending data using CoAP protocol

Question

I'm using Californium API ( https://github.com/eclipse/californium ) to send data using CoAP protocol.

Below is the snippet for both client and server.

Server :

public class HelloWorldServer extends CoapServer {
    /*
     * Application entry point.
     */
    public static void main(String[] args) {
        try {
            // create server
            HelloWorldServer server = new HelloWorldServer();
            server.start();
        } catch (SocketException e) {
            System.err
                    .println("Failed to initialize server: " + e.getMessage());
        }
    }

    /*
     * Constructor for a new Hello-World server. Here, the resources of the
     * server are initialized.
     */
    public HelloWorldServer() throws SocketException {
        // provide an instance of a Hello-World resource
        add(new HelloWorldResource());
    }

    /*
     * Definition of the Hello-World Resource
     */
    class HelloWorldResource extends CoapResource {
        public HelloWorldResource() {
            // set resource identifier
            super("helloWorld");
            // set display name
            getAttributes().setTitle("Hello-World Resource");
        }

        @Override
        public void handleGET(CoapExchange exchange) {
            // respond to the request
            exchange.respond("Hello World!");
        }

        @Override
        public void handlePOST(CoapExchange exchange){
            //System.out.println("Start "+System.currentTimeMillis());
            exchange.accept();           
            //List<String> queries = exchange.getRequestOptions().getURIQueries();
        //    System.out.println("Text Received : "+ exchange.getRequestText().length());
        //    System.out.println("End "+System.currentTimeMillis());
            exchange.respond("Received");


        }
    }
}

Client code :

try {           

            long startTime = System.currentTimeMillis();
            for (int i = 0; i < 1000000; i++) {
                CoapClient client = new CoapClient(new URI("coap://192.168.15.170:5683/helloWorld"));
                CoapResponse response = client.post(str, 0);            

            }
            System.out.println("done");         
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }catch (Exception e) {
            e.printStackTrace();
        }

I'm sending 1000000 records but while sending first it send 65535 records and it wait for few seconds.after waiting for few seconds then it again starts sending.

System Details :

OS : Win 7 64 bit. RAM : 4 GM

Why it wait after 65535 records?

Answer 1

I gone through the Californium.CoAP receives 250 records per second. I have added relay of 4 ms.so that it manage to send less than 250 records/second.

If you sending data from different machine to same CoAP server resource, you need to manage delay accordingly.

CoAP Message Id (MID) ranginf from 1-65565 only.

Also configure Californium.properties properly to work.