HP X.25/9000 User's Guide HP-UX 11i v3 (5900-1523, August 2011)

C Diagnostic messages
Introduction
This appendix describes the diagnostic codes and messages which are a subset of the list defined
by the International Standards Organization (ISO) in IS-8202:1987(E). Only those diagnostics
supported on X.25 for HP 9000 systems are listed. Each message is listed in numerical order by
its diagnostic code and includes an ISO description and explanation.
Refer to Appendix D of the X.25 PSN Connection for a complete list of diagnostic codes and
messages, and to ISO IS-8202:1987(E) for a list of the corresponding cause codes and messages.
Diagnostic message example
An example diagnostic message generated by the network from a CLEAR REQUEST packet is
shown below:
Clear request
LCGN: 0 LCN : 32
Clearing Cause [0] : DTE originated.
Diagnostic [241] :
In the example above, LCGN is the Logical Channel Group Number and LCN is the Logical Channel
Number (the number denoting the logical association between a DTE and DTE connected by a
VC). Refer to the discussion below for more information on cause codes.
Diagnostic codes are generated by the network and may appear in octet 5 of RESTART
INDICATION, RESET INDICATION, or CLEAR INDICATION packets. If a diagnostic field is not
present in a CLEAR INDICATION or RESET INDICATION packet, 0 is returned as the diagnostic
code.
A cause code and message is usually returned from the network with each diagnostic. Diagnostic
codes and messages are usually displayed only when tracing or logging is on, the x25check
utility is run, or cause and diagnostic codes are printed in level 3 application programs. Refer to
the listing of diagnostic codes later in this appendix for more information.
In the descriptions in the diagnostic listing, a REQUEST or ACCEPTED packet refers to a packet
generated by the local application and an INDICATION or CONFIRM packet refers to a packet
received from the network. The requests in which a diagnostic code can be found are shown after
the numeric code of the diagnostic.
Once the application specifies CLEAR or RESET cause and diagnostic codes, this code combination
is used for all RESET REQUEST packets generated by the application. This combination is also
used for the CLEAR REQUEST generated when the application calls close() or shutdown()
on a given socket.
Cause code settings
X.25 automatically resets (silently forces) the network-generated cause code of CLEAR or RESET
REQUEST packets to comply with the applicable CCITT X.25 Recommendation.
• 1980 – The cause is silently forced to zero.
• 1984 – The cause is left at zero or OR'ed with 128 if it is not zero.
• 1988 – The cause is left at zero or OR'ed with 128 if it is not zero.
X.25 does not guarantee that the cause, diagnostic, facility, or clear user data fields of a CLEAR
REQUEST or a RESET REQUEST are delivered to the remote destination because these fields may
be altered by the network, the X.25 implementation (under certain circumstances) or both. In
particular, X.25 discards the clear user data and facility fields of a CLEAR REQUEST when the
facility field is found to be invalid for the given system configuration or when any other error occurs.
When an error occurs on a CLEAR REQUEST, the cause and diagnostic fields delivered to the
network are silently set according to the error.
Introduction 151