Dear Tuan, Thank you for such a propmt answer. > Don't forget you have a transport, network, and link layer header bytes > that factor into the load on the physical interface. Yes, 8 (for UDP) + 20 (for IP) + 18 (for eth). Rigth? > Also, why don't you use usleep() instead of select()? Ok, never heard of 'usleep()' before. Do you think this is a valid approach, I mean, is this close to a real situation? Matias. - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html