I-Data ReRouter - Manual (Page 22)

Installation and Setup
ida ReRouter
22
4.3 Keep Alive Function
The KEEPALIVE feature is a monitor function to check the conneciton
between the transaction program (i.e. the ida ReRouter program) and the
printer. The monitoring of the conneciton is done at defined intervals.
4.3.1 Support for KeepAlive to OS/2
The TCP/IP components for OS/2 offer network attachment for
printers. However, these TCPIP components do not always detect
connection failures if a point-to-point session between the OS2
machine and the device has failed (e.g. in connection with a printer
being abruptly powered off). This may result in serious problems if the
printers comprise IPDS printers in sessions with PSF/2 or PSF/6000.
Now, support for the TCP KEEPALIVE facility has been added to the
TCP/IP components for OS/2 to detect all communcation failures. The
PSF/6000 or PSF/2 direct TCP to send a KEEPALIVE transmission on
a TCP connection remaining inactive for an extended period. If the
KEEPALIVE transmission is not acknowledged, the TCP assumes that
the connection partner has been lost and subsequently reports a failure
to the PSF/6000 or PSF/2.
The frequency of these transmissions depends upon the configuration
of the TCP/IP in the OS/2 environments. On OS/2, the default values
are two hours or more. Both platforms, however, allow the frequency of
KEEPALIVE transmissions to be adjusted. These values apply to all
TCP applications that request KEEPALIVE transmissions.
In the following, you are provided with instructions for using the
KEEPALIVE support facility added to the TCP/IP components for
OS/2.