Echelon OpenLDV - Manual (Page 121)

OpenLDV Programmer’s Guide 113
Table 36. Changing Authentication Keys
Phase One, Lookup Extension Component Is Called
Initially, the current authentication key must match the authentication key configured into the RNI for
the connection to be established. The authentication key fields start with the following values:
RNI Authentication Key ABCD
SCO Current Authentication Key ABCD
SCO Next Authentication Key EFGH
Current Authentication Key in the Database ABCD
Next Authentication Key in the Database EFGH
Phase Two, RNI’s Key Updated
Because the current and next authentication keys filled into the SCO differ, the authentication key
configured into the RNI is incremented so that it matches the next authentication key (EFGH). In
addition, the current authentication key stored in the SCO is updated to match the next authentication
key. The authentication key fields now have the following values:
RNI Authentication Key EFGH
SCO Current Authentication Key EFGH
SCO Next Authentication Key EFGH
Current Authentication Key in the Database ABCD
Next Authentication Key in the Database EFGH
Phase Three, Update Lookup Method Called
The UpdateLookup method is called after the authentication key configured into the RNI, and the
current authentication key in the SCO, have been changed. This method must update the database so
that it is updated with the new values of the current authentication key and the next authentication
key from the SCO. The current and next authentication keys must always be stored in the database,
and can be updated only when the UpdateLookup method is called.
The next time there is a session with this RNI, the lookup extension will fill in the proper value for the
current authentication key. After update lookup has been called, the authentication key fields should
have the following values:
RNI Authentication Key EFGH
SCO Current Authentication Key EFGH
SCO Next Authentication Key EFGH
Current Authentication Key in the Database EFGH
Next Authentication Key in the Database EFGH
Creating a Custom Lookup Extension in C++
This section describes the procedure for creating the framework for a custom
lookup extension component in C++ using Microsoft Visual Studio 2008. Use a
similar procedure for Microsoft Visual Studio 2010, or later releases.