IEC61850 Server: no buffer-overflow bit after a client sends wrong EntryID

IEC61850 Server: no buffer-overflow bit after a client sends wrong EntryID

Summary

When a client reconnects and sends wrong EntryID as request for buffered reports the IEC61850 Server (zenon Logic I/O driver) logs an error and responses this MMS.Write negative. Then the IEC61850 Server sends all buffered reports - so acts like by EntryID=0. But when in the meantime the buffer was overflowed the Server does not signalizes it with buffer-overflow flag in first report.

Description

When a client reconnects and sends wrong EntryID as request for buffered reports the IEC61850 Server (zenon Logic I/O driver) logs an error and responses this MMS.Write negative. Then the IEC61850 Server sends all buffered reports - so acts like by EntryID=0. But when in the meantime the buffer was overflowed the Server does not signalizes it with buffer-overflow flag in first report.

Solution

The Server now sets buffer-overflow flag in the first report after a client reconnects and requests buffered reports using invalid EntryID.

Information

In the IEC61850 Standard there is no description of such scenario: invalid EntryID received after buffer-overflow.

We decided to close this gap in definition like following: on invalid EntryID the Server cannot deliver requested reports (reports since this EntryID) - it does not have such reports in buffer. This situation is similar like in the situation of buffer-overflow.



Issue Number: 30469
Fixed on Date: 25.11.2013
Versions: 7.10 0 BUILD 9356