private String receiveDataUdp(InetSocketAddress clientAddress) throws IOException, JSONException {
    EmployeeList employees = new EmployeeList();
    DatagramSocket datagramServer = new DatagramSocket(clientAddress);
    byte dataFromServer[] = new byte[2048];
    boolean isTimeExpired = false;
    datagramServer.setSoTimeout((int) SECONDS.toMillis(PROTOCOL_GROUP_TIMEOUT - 5));

    System.out.println(
        "[INFO] -----------------------------------------\n"
            + "[INFO] Collecting information from nodes....");
    while (!isTimeExpired) {
      DatagramPacket datagramPacketacket =
          new DatagramPacket(dataFromServer, dataFromServer.length);
      try {
        datagramServer.receive(datagramPacketacket);
      } catch (SocketTimeoutException e) {
        System.out.println(
            "[WARNING] -----------------------------------------\n"
                + "[WARNING] Waiting time expired...");
        isTimeExpired = true;
        continue;
      }
      String receivedJson = (String) deserialize(datagramPacketacket.getData());
      System.out.println("[INFO] " + "Received employee in JSON: " + receivedJson);
      employees.add(jsonToEmployee(receivedJson));
    }
    datagramServer.close();
    return employeeToXml(employees);
  }
  /**
   * Creates a new <tt>RawPacket</tt> from a specific <tt>DatagramPacket</tt> in order to have this
   * instance receive its packet data through its {@link #read(byte[], int, int)} method. Returns an
   * array of <tt>RawPacket</tt> with the created packet as its first element (and <tt>null</tt> for
   * the other elements).
   *
   * <p>Allows extenders to intercept the packet data and possibly filter and/or modify it.
   *
   * @param datagramPacket the <tt>DatagramPacket</tt> containing the packet data
   * @return an array of <tt>RawPacket</tt> containing the <tt>RawPacket</tt> which contains the
   *     packet data of the specified <tt>DatagramPacket</tt> as its first element.
   */
  protected RawPacket[] createRawPacket(DatagramPacket datagramPacket) {
    RawPacket[] pkts = rawPacketArrayPool.poll();
    if (pkts == null) pkts = new RawPacket[1];

    RawPacket pkt = rawPacketPool.poll();
    if (pkt == null) pkt = new RawPacket();

    pkt.setBuffer(datagramPacket.getData());
    pkt.setFlags(0);
    pkt.setLength(datagramPacket.getLength());
    pkt.setOffset(datagramPacket.getOffset());

    pkts[0] = pkt;
    return pkts;
  }
  private void runOnDtlsTransport(StreamConnector connector) throws IOException {
    DtlsControlImpl dtlsControl = (DtlsControlImpl) getTransportManager().getDtlsControl(this);
    DtlsTransformEngine engine = dtlsControl.getTransformEngine();
    final DtlsPacketTransformer transformer = (DtlsPacketTransformer) engine.getRTPTransformer();

    byte[] receiveBuffer = new byte[SCTP_BUFFER_SIZE];

    if (LOG_SCTP_PACKETS) {
      System.setProperty(
          ConfigurationService.PNAME_SC_HOME_DIR_LOCATION, System.getProperty("java.io.tmpdir"));
      System.setProperty(
          ConfigurationService.PNAME_SC_HOME_DIR_NAME, SctpConnection.class.getName());
    }

    synchronized (this) {
      // FIXME local SCTP port is hardcoded in bridge offer SDP (Jitsi
      // Meet)
      sctpSocket = Sctp.createSocket(5000);
      assocIsUp = false;
      acceptedIncomingConnection = false;
    }

    // Implement output network link for SCTP stack on DTLS transport
    sctpSocket.setLink(
        new NetworkLink() {
          @Override
          public void onConnOut(SctpSocket s, byte[] packet) throws IOException {
            if (LOG_SCTP_PACKETS) {
              LibJitsi.getPacketLoggingService()
                  .logPacket(
                      PacketLoggingService.ProtocolName.ICE4J,
                      new byte[] {0, 0, 0, (byte) debugId},
                      5000,
                      new byte[] {0, 0, 0, (byte) (debugId + 1)},
                      remoteSctpPort,
                      PacketLoggingService.TransportName.UDP,
                      true,
                      packet);
            }

            // Send through DTLS transport
            transformer.sendApplicationData(packet, 0, packet.length);
          }
        });

    if (logger.isDebugEnabled()) {
      logger.debug("Connecting SCTP to port: " + remoteSctpPort + " to " + getEndpoint().getID());
    }

    sctpSocket.setNotificationListener(this);
    sctpSocket.listen();

    // FIXME manage threads
    threadPool.execute(
        new Runnable() {
          @Override
          public void run() {
            SctpSocket sctpSocket = null;
            try {
              // sctpSocket is set to null on close
              sctpSocket = SctpConnection.this.sctpSocket;
              while (sctpSocket != null) {
                if (sctpSocket.accept()) {
                  acceptedIncomingConnection = true;
                  break;
                }
                Thread.sleep(100);
                sctpSocket = SctpConnection.this.sctpSocket;
              }
              if (isReady()) {
                notifySctpConnectionReady();
              }
            } catch (Exception e) {
              logger.error("Error accepting SCTP connection", e);
            }

            if (sctpSocket == null && logger.isInfoEnabled()) {
              logger.info(
                  "SctpConnection " + getID() + " closed" + " before SctpSocket accept()-ed.");
            }
          }
        });

    // Notify that from now on SCTP connection is considered functional
    sctpSocket.setDataCallback(this);

    // Setup iceSocket
    DatagramSocket datagramSocket = connector.getDataSocket();
    if (datagramSocket != null) {
      this.iceSocket = new IceUdpSocketWrapper(datagramSocket);
    } else {
      this.iceSocket = new IceTcpSocketWrapper(connector.getDataTCPSocket());
    }

    DatagramPacket rcvPacket = new DatagramPacket(receiveBuffer, 0, receiveBuffer.length);

    // Receive loop, breaks when SCTP socket is closed
    try {
      do {
        iceSocket.receive(rcvPacket);

        RawPacket raw =
            new RawPacket(rcvPacket.getData(), rcvPacket.getOffset(), rcvPacket.getLength());

        raw = transformer.reverseTransform(raw);
        // Check for app data
        if (raw == null) continue;

        if (LOG_SCTP_PACKETS) {
          LibJitsi.getPacketLoggingService()
              .logPacket(
                  PacketLoggingService.ProtocolName.ICE4J,
                  new byte[] {0, 0, 0, (byte) (debugId + 1)},
                  remoteSctpPort,
                  new byte[] {0, 0, 0, (byte) debugId},
                  5000,
                  PacketLoggingService.TransportName.UDP,
                  false,
                  raw.getBuffer(),
                  raw.getOffset(),
                  raw.getLength());
        }

        // Pass network packet to SCTP stack
        sctpSocket.onConnIn(raw.getBuffer(), raw.getOffset(), raw.getLength());
      } while (true);
    } finally {
      // Eventually, close the socket although it should happen from
      // expire().
      synchronized (this) {
        assocIsUp = false;
        acceptedIncomingConnection = false;
        if (sctpSocket != null) {
          sctpSocket.close();
          sctpSocket = null;
        }
      }
    }
  }
  /**
   * Listens for incoming datagrams, stores them for reading by the <tt>read</tt> method and
   * notifies the local <tt>transferHandler</tt> that there's data to be read.
   */
  public void run() {
    DatagramPacket p = new DatagramPacket(buffer, 0, PACKET_RECEIVE_BUFFER_LENGTH);

    while (!closed) {
      try {
        // http://code.google.com/p/android/issues/detail?id=24765
        if (OSUtils.IS_ANDROID) p.setLength(PACKET_RECEIVE_BUFFER_LENGTH);

        receivePacket(p);
      } catch (IOException e) {
        ioError = true;
        break;
      }

      /*
       * Do the DatagramPacketFilters accept the received DatagramPacket?
       */
      DatagramPacketFilter[] datagramPacketFilters = getDatagramPacketFilters();
      boolean accept;

      if (!enabled) accept = false;
      else if (datagramPacketFilters == null) accept = true;
      else {
        accept = true;
        for (int i = 0; i < datagramPacketFilters.length; i++) {
          try {
            if (!datagramPacketFilters[i].accept(p)) {
              accept = false;
              break;
            }
          } catch (Throwable t) {
            if (t instanceof ThreadDeath) throw (ThreadDeath) t;
          }
        }
      }

      if (accept) {
        RawPacket pkts[] = createRawPacket(p);

        for (int i = 0; i < pkts.length; i++) {
          RawPacket pkt = pkts[i];

          pkts[i] = null;

          if (pkt != null) {
            if (pkt.isInvalid()) {
              /*
               * Return pkt to the pool because it is invalid and,
               * consequently, will not be made available to
               * reading.
               */
              poolRawPacket(pkt);
            } else {
              RawPacket oldPkt;

              synchronized (pktSyncRoot) {
                oldPkt = this.pkt;
                this.pkt = pkt;
              }
              if (oldPkt != null) {
                /*
                 * Return oldPkt to the pool because it was made
                 * available to reading and it was not read.
                 */
                poolRawPacket(oldPkt);
              }

              if (videoRecorder != null) videoRecorder.recordData(pkt);

              if ((transferHandler != null) && !closed) {
                try {
                  transferHandler.transferData(this);
                } catch (Throwable t) {
                  /*
                   * XXX We cannot allow transferHandler to
                   * kill us.
                   */
                  if (t instanceof ThreadDeath) {
                    throw (ThreadDeath) t;
                  } else {
                    logger.warn("An RTP packet may have not been" + " fully handled.", t);
                  }
                }
              }
            }
          }
        }
        rawPacketArrayPool.offer(pkts);
      }
    }
  }