The Question is:
TELNET devices TN* and DECserver 90
My application is gathering messages over serial lines connected to the
DECserver ports and its behaviour is optimal using LAT devices.
Now I am forced to change to TCP/IP.
As in various wizard discussions recommended I defined on DECserver:
change telnet listener 2001 port 1
change telnet listener 2001 connections enable
and in VMS:
telnet <address>/create_session 2001 2001
And my application runs well with unchanged qio-read.
BUT: on network or power failure nothing happens to the TNA2001! Thus the
application is not able to recognize a failure and to reconnect.
Is there a solution thru more detailed DECserver or TELNET configuration? Or is
this way too simple so that I must try other techniques, e.g. direct socket
programming ( where do I find examples )?
ucx sh vers
Digital TCP/IP Services for OpenVMS Alpha Version V4.1 - ECO 8
on a AlphaStation 255/300 running OpenVMS V7.1
The Answer is :
Poll the device (via ping or in-band character transfer) at periodic
Consider the UCX$TELNET_KEEPALIVE logical name, or its equivilent in
V5 and later: SET SERVICE FTP/SOCKET_OPTIONS=KEEPALIVE mechanism?
Consider an upgrade to TCP/IP Services V5.0A, as V4.1 is very old.