PQ62464: NEED TO HAVE AN ABILITY TO SET KEEPALIVE TIMEOUT OPTION FOR EACHIIOP CONNECTION IN WEBSPHERE FOR Z/OS SERVER

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APAR status
Closed as program error.

Error description
Currently WebSphere for z/OS Server doesn't have a timeout
function for IIOP connection. When establishing a connection
from a remote client to a server, this prevents to re-use
the same server port which was previously used by a gone_away
client.
A similar function was already provided for HTTP connection
by BBOC_HTTP_PERSISTENT_SESSION_TIMEOUT.
Local fix Problem summary
****************************************************************
* USERS AFFECTED: All users of WebSphere Application Server    *
*                 V4.0.1 for z/OS and OS/390                   *
****************************************************************
* PROBLEM DESCRIPTION: If the client has gone away             *
*                      (e.g. rebooted) in such a way that the  *
*                      server never got notified, the server   *
*                      side TCP/IP session will remain active  *
*                      forever.  It may be desireable to make  *
*                      these sessions go away.                 *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
If a client, for example a workstation, is using IIOP over
TCP/IP to communicate with the server and the client goes away
by rebooting, unplugging a cable, etc., the server TCP/IP stack
may never be notified.  This causes the Control Region to
retain the session forever.  This ties up resources on the
server.  It also makes the client-side port unusable to
reach this server because the server thinks it already has
a session from this client/port and won't accept another one.
The client can select another client-side port, but over time
this problem could invalidate numerous client-side ports
causing delays in finding a usable port.
Problem conclusion
TCP/IP provides options via SO_KEEPALIVE and SOCK_TCP_KEEPALIVE
that will cause TCP/IP to monitor for idle sessions and attempt
to contact the client TCP/IP stack to ensure the client is
still present.  If it is not, then the server-side session will
be closed.  The SOCK_TCP_KEEPALIVE option was introduced by
TCP/IP APAR 
PQ18618.  Please see that APAR for documentation
on how the time values specified on SOCK_TCP_KEEPALIVE affect
TCP/IP behaviour.  WebSphere does not set these socket options
by default, but will do so if the new environment variables
IIOP_SERVER_SESSION_KEEPALIVE or
SSLIIOP_SERVER_SESSION_KEEPALIVE (for SSL IIOP sessions) are
set.  If you do not have 
PQ18618 installed and specify the
environment variables listed above, the setsockopt for
SOCK_TCP_KEEPALIVE will fail and you will receive message
BBOU0639E indicating setsockopt() failed with a RC of
ENOPROTOOPT (1109).  When a session is closed because the time
expired and the server TCP/IP stack was unable to contact the
client TCP/IP stack, message BBOU0244E will be logged indicating
a failure with RC of ETIMEDOUT (1127).

The following publication was revised as a result
of APAR PQ62464:
________________________________________________________________
WebSphere Application Server V4.0.1 for z/OS and OS/390
Installation and Customization
GA22-7834-05
________________________________________________________________
This APAR requires changes to documentation.

NOTE: Periodically, we refresh the documentation on our
Web site, so the changes might have been made before you
read this text. To access the latest on-line
documentation, go to the product library page at:


http://www.ibm.com/software/webservers/appserv/zos_os390/
________________________________________________________________

Appendix A, pg. 387 (new section)

IIOP_SERVER_SESSION_KEEPALIVE=n

This variable, if set, defines the value in seconds provided to
TCP/IP on the SOCK_TCP_KEEPALIVE option for the IIOP listener.
The function of this option is to verify if idle sessions are
still valid by polling the client TCP/IP stack. If the client
does not respond, the session is closed. If the client goes away
without notifying the server, it would unnecessarily leave the
session active on the server side. Use this option to clean up
these unnecessary sessions. See TCP/IP APAR 
PQ18618 for more
information about the TCP/IP SOCK_TCP_KEEPALIVE option.
Notes:
If the environment variable is not set, the TCP/IP option is not
set.
Setting the SOCK_TCP_KEEPALIVE option generates network traffic
on idle sessions, which can be undesirable.
Example:
IIOP_SERVER_SESSION_KEEPALIVE=3600

...
________________________________________________________________

Appendix A, pg. 398 (new section)

SSLIIOP_SERVER_SESSION_KEEPALIVE=n

This variable, if set, defines the value in seconds provided to
TCP/IP on the SOCK_TCP_KEEPALIVE option for the SSL IIOP
listener. The function of this option is to verify if idle
sessions are still valid by polling the client TCP/IP stack. If
the client does not respond, the session is closed. If the
client goes away without notifying the server, it would
unnecessarily leave the session active on the server side. Use
this option to clean up these unnecessary sessions. See TCP/IP
APAR 
PQ18618 for more information about the TCP/IP
SOCK_TCP_KEEPALIVE option.
Notes:
If the environment variable is not set, the TCP/IP option is not
set.
Setting the SOCK_TCP_KEEPALIVE option generates network traffic
on idle sessions, which can be undesirable.
Example:
SSLIIOP_SERVER_SESSION_KEEPALIVE=3600

...
________________________________________________________________

APAR PQ62464 is associated with SERVICE LEVEL W401088 of
WebSphere Application Server V4.0.1 for z/OS and OS/390.
Temporary fix Comments
APAR information
APAR number PQ62464
Reported component name WASKBASE
Reported component ID 5655A9801
Reported release 400
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Submitted date 2002-06-22
Closed date 2002-07-31
Last modified date 2002-09-04

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:
UQ68406

Modules/Macros
BBOCSESS BBOCSSES BBOUBINF      

Fix information
Fixed component name WASKBASE
Fixed component ID 5655A9801

Applicable component levels
R401 PSY UQ68406    UP02/08/07 P F208

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Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS
Operating system(s):
Software version: 400
Software edition:
Reference #: PQ62464
IBM Group: Software Group
Modified date: Sep 4, 2002