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

[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 ?

Cheers
Pascal


On Mon, May 10, 2010 at 2:33 PM, Klaus Darilion <
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>>,
>>
>>
>> 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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