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Re: Is nagle disabled?



Le quintidi 25 fructidor, an CCXXIV, Rob van der Putten a écrit :
> I use netcat6. From man nc;
> nc6 --continuous --exec cat -l -p <port>
> So the data goes from nc to cat and then back to nc.
> 
> Timestamps (epoch.microseconds) are dumped to a file on transmission and to
> an other file on reception of the 'echo'. Further check with tcpdump.
> Experiment on LAN and experiment over DSL;
> When the time between the bits of data is larger then the RTT, data is send
> at two bytes per TCP packet.

With that kind of test, the reply comes immediately, the ACK is bundled with
the reply, therefore making delayed ACK invisible.

The way you implemented the echo server, with several applications
communicating with each other, is irrelevant because it is all invisible to
the network stack.

If you want to observe delayed ACK, you need to use a kind of server where
the reply does not come immediately in the same TCP stream. A discard server
would be the simplest example.

Regards,

-- 
  Nicolas George

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