private void sendConnectionRequest(final String targetId, final Socket controlConnection) throws IOException {
final Message requestMessage = MessageStaticFactory.newSTUNMessageInstance(STUNMessageClass.REQUEST,
STUNMessageMethod.CONNECTION_REQUEST);
requestMessage.addAttribute(new Username(targetId));
requestMessage.addAttribute(new ReversalAttribute());
logger.info("send connection request for target {}", targetId); //$NON-NLS-1$
requestMessage.writeTo(controlConnection.getOutputStream());
}