[SR-Users] Configuring TCP keep alive and connection lifetime

[Klaus Darilion]

Am 11.05.2010 10:04, schrieb Pascal Maugeri:
> Hi
>
> I just checked these parameters in runtime (using sysctl -a | grep
> "tcp_keepalive") and I get:
>
> net.ipv4.tcp_keepalive_time = 7200
> net.ipv4.tcp_keepalive_probes = 9
> net.ipv4.tcp_keepalive_intvl = 75
>
> I recognize the "75" value used in the delay between my k.a. ! It gets
> clearer :-)
>
> My question is: does kamailio set somewhow (parameter of source code
> constant definition) this net.ipv4.tcp_keepalive_intvl parameter ? Or
> should I fine tune myself in the OS kernel configuration ?

Probably the fastest way is to grep the source code for 
tcp_keepalive_intvl and similar (tcp_keepidle ...)

regards
klaus

>
> Cheers
> Pascal
>
>
> On Mon, May 10, 2010 at 2:33 PM, Klaus Darilion
> <klaus.mailinglists at pernau.at <mailto:klaus.mailinglists at pernau.at>> wrote:
>
>     Hi Pascal!
>
>     The TCP keepalive is not an application layer keep alive, but
>     Kamailio just sets the SO_KEEPALIVE socket option. The the TCP keep
>     alive is implemented and performed by the operating systems.
>
>     Thus, if you want to tweak the TCP keep alive, then you have to
>     tweak the kernel.
>
>     regards
>     Klaus
>
>     Am 07.05.2010 16:20, schrieb Pascal Maugeri:
>
>         "kamailio" <users at lists.kamailio.org
>         <mailto:users at lists.kamailio.org>
>         <mailto:users at lists.kamailio.org
>         <mailto:users at lists.kamailio.org>>>,
>
>
>         Hi
>
>         I am sorry to ask again about this topic but I don't understand
>         yet how
>         the TCP keep-alive are sent.
>
>         With Kamailio 3.0.1 and the following configuration:
>
>             tcp_keepalive=yes
>             tcp_keepidle=10
>             tcp_connection_lifetime=3600
>
>
>         The TCP connection is kept alive and TCP Keep-Alive packets are sent
>         when the TCP connection is idle.
>
>         But I don't understand why the time between KA is not linear:
>
>         first KA is sent 10 seconds after last last TCP message. This is
>         logical
>         and connected with the tcp_keepidle=10 configuration.
>
>         then 2nd KA is sent 75 seconds after first KA
>
>         Then my client sends some traffic and 23 seconds after last
>         message, a
>         new KA is sent. Another time it was 54 seconds. etc. etc.
>
>         Could you explain me where do come from these values of 75
>         seconds, 23, 54 ?
>
>         Everything works well: my client behind NAT is kept connected
>         but I'd
>         like to understand why it does work :-)
>
>         Thanks in advance,
>         Pascal
>
>
>
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