mhg@MITRE-BEDFORD.ARPA.UUCP (06/03/86)
Does any one know the system service call (and I am assuming that there is one) to find out if a remote DECnet node is available WITHOUT establishing a link to it? I am making an exhancement to an existing program that was written before we had DECnet. I am using BASIC under VMS v4.2. Thanks in advance. Mark H. Granoff (mhg@mitre-bedford)
LEICHTER-JERRY@YALE.ARPA.UUCP (06/05/86)
Does any one know the system service call....
Mark H. Granoff (mhg@mitre-bedford)
There is no way to do this, at present. (In general, a node doesn't even
KNOW what other nodes are reachable - non-routing nodes almost never know,
and even routers know only about their own areas and - for area routers -
other routers.)
The quickest known approach is to use the following hack: Choose and reserve
some DECnet object number, say 123. NEVER define an object numbered 123.
The, to determine if node FOO is reachable, try to connect to FOO::"TASK=123".
This will always fail, but a check of the error returned will tell you why.
(The reason for using the non-existent object number hack is that it avoids
ever creating a process on the remote system if you DO manage to reach it.)
-- Jerry
-------