Idle Timeout vs Keep Alive

Hi,

 

One of our Virtual Server is using a TCP Profile having for Value :

 

Idle Timeout = 1800 secs Keep Alive = 1800 secs.

 

I'm seeing inconsistency on the amount of Keep Alive send by the Big-IP to the client before Resetting the connection.

 

Sometimes Big-IP send 2 Keep Alive and send the RST Packet after 90 minutes. Sometimes it does send 6 Keep Alive and send the RST after 3h 30 minutes. Sometimes it does send the RST PAcket straight after 30 minutes Idle.

 

Do you know how this is handle by LTM when the Keep Alive and Idle Timeout value are identical ?

 

Thanks in advance, Flo