When a Client that uses aliased Nodes detects a communication problem with the Server, the Client can return to the GDS and request a new AliasNodeList for the AliasName. The original Server may recover and again be listed in the GDS, but the Client is not required to switch back. Figure B-11 provides an overview of this process.


Figure B-11 - Example Client Process for Server subscription with errors

It is important to remember that the FindAlias Method will return a list of NodeIds (and Servers) that meet the requested AliasName search string. It is up to the Client to determine if the NodeId that is returned is the same Server or on a different Server or if the next NodeId should be used instead of the first.


ANSI/ISA-S5.1-1984 (R 1992), Instrumentation Symbols and Identification