Using the Keep-alive Option


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Keep-alive is a networking operation that periodically checks the viability of a network connection between the Workstation handler and a Workstation client if no traffic has occurred over that connection within a specified period of time.

You can request the keep-alive option by adding the -K option to the WSL CLOPT entry in the SERVERS section of the UBBCONFIG file. The -K option accepts the following arguments: client, handler, both, or none.

Use This Option...	To...
-K client	Generate keep-alive messages from the client machines. If the keep-alive message is not acknowledged, the client machine considers the network down. Subsequent ATMI calls fail with a tperrno of TPESYSTEM.
-K handler	Generate keep-alive messages from the handler machine. If the keep-alive message is not acknowledged, the handler machine considers the network down. The handler then cleans up the entry associated with the client that does not respond. This reduces the possibility that the handler will exhaust the number of clients that a workstation can multiplex at one time (as specified by -x) with stale clients.
-K both	Generate keep-alive message from both the client and handler machines. The availability and timeout thresholds for this component are determined by tunable parameters in the operating system.
-K none	Turn off the keep-alive option. Using this setting has the same effect as not specifying -K at all.

Your entry in the UBBCONFIG file should look like the following:

WSL SRVGRP="WSLGRP" SRVID=1000 RESTART=Y GRACE=0
CLOPT="-A -- -n //ws.beasys.com:5120 -d /dev/tcp -K both"

In the example, -K turns on keep-alive checking on both the Workstation client and the server.

For details about the format of a WSL entry in UBBCONFIG, see WSL(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference.

Note: Any timeout period that you specify applies to the entire system. If you specify a timeout with one application in mind, and you later change the amount of time specified, all applications that use keep-alive are also affected.

Limitations When Using the Keep-alive Option

The keep-alive option is supported only on platforms for which the BEA Tuxedo system uses sockets:

Tru64 UNIX
HP UX
Windows

You cannot use this option on any other platform. The BEA Tuxedo system lets you specify the -K option for any server machine, but it will not execute it properly on any platform other than those previously listed. If you try to perform a keep-alive operation on any other platform, your attempt fails and a message is written to the userlog (once per process for the WSH). Processing continues normally.

Note: The keep-alive operation works only for TCP/IP communications.