+ *
+ * <center><table><tr><td><b>Top</b> <td> [\ref index]::[\ref GRAS_API]
+ * <tr><td><b>Prev</b> <td> [\ref GRAS_dd]
+ * <tr><td><b>Next</b> <td> [\ref GRAS_msg]
+ * <tr><td><b>Down</b> <td> [\ref GRAS_sock_create] </table></center>
+ *
+ * The model of communications in GRAS is very close to the BSD socket one. To get two hosts
+ * exchanging data, one of them need to open a <i>server</i> socket on which it can listen for incoming messages
+ * and the other one must connect a <i>client</i> socket onto the server one.
+ *
+ * If you need an example of this, check \ref GRAS_ex_ping.
+ *