[users@httpd] Version of TCP

[Dusan Geratovic <du...@yahoo.com>]

Which version of TCP protocol does the Apache Server 2.2 use? I have noticed that in case of packet loss TCP window does not shrink to the half size (like standard version does), but to the 20, 30% of its original size. I suppose that the some modified version is used (High Speed TCP or something like that).

Thanks in advance.

Re: [users@httpd] Version of TCP

[Mark Montague <ma...@catseye.org>]

On September 26, 2011 4:25 , Dusan Geratovic <du...@yahoo.com> 
wrote:
> Which version of TCP protocol does the Apache Server 2.2 use? I have 
> noticed that in case of packet loss TCP window does not shrink to the 
> half size (like standard version does), but to the 20, 30% of its 
> original size. I suppose that the some modified version is used (High 
> Speed TCP or something like that).
>

Apache HTTP Server uses the version of TCP provided by the operating 
system it is running on.   The Apache Portable Runtime (APR) library is 
used to provide a consistent interface to Apache HTTP Server regardless 
of operating-system-specific variations.  See 
https://apr.apache.org/docs/apr/1.4/group__apr__network__io.html and 
https://apr.apache.org/docs/apr/1.4/group__apr__sockopt.html

I'm not aware of anything in Apache HTTP Server or APR that controls TCP 
windowing, although they do use the TCP_NODELAY, TCP_CORK, and 
TCP_NOPUSH socket options: see 
http://www.techrepublic.com/article/tcpip-options-for-high-performance-data-transmission/1050878

 From my limited knowledge, I suspect the windowing behavior you are 
seeing is due to behavior of your operating system kernel.

--
   Mark Montague
   mark@catseye.org


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