MSG_process_create("send", sender_fun, NULL, MSG_get_host_by_name("Tremblay"));
MSG_process_create("receive", receiver_fun, NULL, MSG_get_host_by_name("Tremblay"));
MSG_process_create("send", sender_fun, NULL, MSG_get_host_by_name("Tremblay"));
MSG_process_create("receive", receiver_fun, NULL, MSG_get_host_by_name("Tremblay"));