David Woolley <[email protected]> wrote: > E-Mail Sent to this address will be added to the BlackLists wrote: > >> >> I can perhaps see idling the connection to keep it open when the >> poll rate is at ~ 1 minute, however what about when the poll >> rate decreases to ~ 17 minutes? (or less often if so configured) > > There are no network cost in keeping a TCP connection "idling", as there > is no traffic in that state. (The exception is if you enable > keepalives, and you wait hours between real traffic, but even then the > traffic is very very small.)
It would be very unwise to use TCP for something like NTP. Information sent by an application via a TCP socket will be re-sent by the OS when no acknowledgement is received. When the original network packet had been lost, the receiver will get a retransmitted copy which contains the original timestamp but which arrives much later in time. (the re-try timer in TCP is usually in the order of seconds) It is better to send a time message and lose it (with UDP), than to receive it later because it has been re-transmitted. With UDP the re-transmit is done at the application layer, and the application can put fresh time information in the re-transmission. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
