[ros-dev] Loopback problem

[Ged Murphy]

Joseph Galbraith wrote:
> Phillip Susi wrote:
>   
>> Ge van Geldorp wrote:
>>     
>>> I'm not arguing that delayed ACK is incorrect, but 2.5 sec???
>>> Searching the
>>> Internet, 200ms seems a much more accepted value. This is also the value
>>> used by the MS stack:
>>> http://www.microsoft.com/technet/itsolutions/network/deploy/depovg/tcpip2k.m
>>>
>>> spx (under "Delayed Acknowledgements").
>>>       
>> That does sound like a more reasonable value, but if nagling is
>> disabled, it should not matter.
>>     
>
> If an app is going to send one byte at a time, disabling
> the nagle algorithm is _exactly_ the _wrong_ thing to do!
>
> The nagle algorithm exists precisely so that applications can
> send one byte at a time and not have sucky performance.
>   

We know this. If you read back through the previous mails, you'll see 
that  disabling the algorithm was suggested for testing purposes only.

> But any app that does:
>
>   send();
>   send();
>   .
>   .
>   .
>   send();
>   recv();
>
> Should not disable the nagel algorithm except in rare (I can't
> think of any) circumstances.
>   

I can give you a few (besides debugging) :

- Streaming media
- X servers
- network games

If packet timing is more important that consuming large amounts of 
bandwidth with packet overhead, it's perfectly reasonable to disable it.

Ged.