ACC X.25 Protocol User's Guide

Appendix A 135
X.25 Status and Completion Messages
Unsolicited Status Messages
ST25RXUA (74) X.25 Link disconnected or restarted due to a received
UA (Unnumbered Acknowledgment) frame. Bit 7 of the
mrqstat field will indicate the current up/down state of
the link.
ST25RUFR (75) X.25 Link disconnected or restarted due to a received
unsolicited final response f rame. Bit 7 of the mrqstat
field will indicate the current up/down state of the link.
ST25ENF (77) X.25 Link ZLU enable failed due to an invalid
configuration. Check the various configuration
parameters, particularly the poll and select words for
this X.25 link ZLU.
ST25ENB (78) X.25 Link ZLU has been enabled.
ST25TPA (79) X.25 Link ZLU has been activated. This link can now
accept inbound I-frames.
ST25TPD (80) X.25 Link ZLU has been deactivated. Note that a
deactivated link will not accept inbound data. The ACC
MUX will automatically respond with a level 2 RNR
whentheremotesideofthelinkattemptstosendan
HDLC/LAP-B I-frame to a deactivated link.
ST25DSBRQ (81) A D ISABLE request has been issued to this X.25
link ZLU. This status normally begins the link
shutdown process. When the shutdown processing is
complete, a link disabled status (82) is received.
ST25DSB (82) X.25 link ZLU has been disabled. The X.25 link is now
fully shutdown and will not respond to any
HDLC/LAP-B protocol packets.
ST25LNCTO (83) An X.25 link control timeout has occurred. This
indicates that the remote end of the link has not
responded to a protocol packet within the appropriate
amount of time. For example, when a Restart Request
packet is sent, the remote end must respond within
timer T20 seconds. This status message is sent when
the timer expires without having seen a response from
the remote end of the link.
ST25LNNBF (84) X.25 link buffer shortage has occurred. This
indicates that the MUX firmware was unable to find a
free outbound buffer for sending a low-level protocol
packet (e.g. RR or RNR). This can be caused by