CA-GTS new option KEEPALIVE and TCPKEEPALIVE to prevent losing connection

Document ID : KB000124119
Last Modified Date : 04/01/2019
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Question:
PTF RO88556 supports new parameters KEEPALIVE and TCPKEEPALIVE in the CA GTS TCPIPCxx and TCPIPSxx parmlib members.  These new parameters affect the ChekPlex feature of CA JCLCheck.  

How do these parameters work? 
Environment:
CA JCLCheck release 12.0
CA GTS release 12.0
Answer:
To prevent losing connections between GTS servers, two new CA GTS parameters (KEEPALIVE(ON), and TCPKEEPALIVE(value)) are available to allow you to specify a timeout value to be used in place of the configuration default value from the TCP/IP stack.  These parameters are set in the CA GTS, and therefore no change to TCP/IP is necessary.

Usage: Add the following parameters to member TCPIPCxx, and TCPIPSxx in the CA GTS CAGSPARM library.

KEEPALIVE(ON)  - Make a SETSOCKOPT call to enable 'SO_KEEPALIVE' for the TCP/IP connection.  The default is KEEPALIVE(OFF).
TCPKEEPALIVE(number) -  Make a SETSOCKOPT call to set a value (in seconds) for TCP_KEEPALIVE.  The default value is TCPKEEPALIVE(0).   
 
Example:
 
KEEPALIVE(ON)
TCPKEEPALIVE(1800)
The above parameters set a timeout value of 1800 seconds, or 30 minutes.

These parameters may be set on both ends of the connections.   If you are not experiencing connection problems between GTS servers, then it's not necessary to set these parameters.

To display the connection status, run the following console commands:
> F cagts,TCPCLNT INFO
> F cagts,TCPSRVR INFO           
 
 
Additional Information:
 Information on SO_KEEPALIVE and TCP_KEEPALIVE:
 IBM manual "z/OS Communications Server:  IP Sockets Application Programming Interface Guide and Reference