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

[Klaus Darilion]

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>>,
>
> 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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