Re: Concerns about changing TCP/IP keep alive time.

On 23-Feb-2012 11:03 , rob@xxxxxxxxx wrote:

I recently got an update to a Domino ticket that went like this:

Looking at the current data from netstat the GDDATA system has
2872 sessions from LDAP in close2 status.
These are sessions that will Eventually close.

One thing we can do is drop the keep alive time.

This is the TCP parameter that limits how long a dead but not
closed session will hold the socket open.
The default is 2 hours, We could cut that to 15 minutes and
drop the CLO2 session count ,

And I confirmed that he wants me to change from
CHGTCPA TCPKEEPALV(255)
to
CHGTCPA TCPKEEPALV(15)

My dilemma is that I can't remember why I have it set to that on this
one lpar and I am hoping that this change will not adversely affect
ftp or anything. I am going to start documenting changes to system
values and such. That being said, any concerns about this change?

In an application, in this scenario apparently LDAP, there would best be an ability to set any pertinent timeouts specific to the entire application or within some subset(s) of processing; i.e. the application being configurable, rather than restricted to operate within more global configuration defaults. That is to suggest... Any sockets application built over the TCP/IP should not limit its timeout settings to the global\system defaults to make the feature more usable.

_i Retrieve TCP/IP Attributes (QtocRtvTCPA) API i_
http://publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/apis/qtocrtvtcpa.htm
"
...
_TCP keep alive_ The amount of time, in minutes, that TCP waits before sending out a probe to the other side of a connection. The probe is sent when the connection is otherwise idle, even when there is no data to be sent.

The transmission of keep-alive packets is controlled by individual sockets applications through use of the SO_KEEPALIVE socket option. For more information, Sockets Programming in the iSeries Information Center.
"

Regards, Chuck