uaCap:Redundancy NonTransparent

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URN:          https://opcfoundation.org/wiki/index.php/Redundancy/ServerNon-TransparentFailover

Description
Client is aware that Server failover has occurred. When a Server fails, the number of actions required by Client depends on the failover mode supported by the Server.
There are four failover modes: Cold, Warm, Hot and HotAndMirrored. Failover for this type of redundancy requires the Client to monitor Server status and to switch to a backup Server if it detects a failure. The failover method tells the Client what it must do when connecting to a Server and when a failure occurs. Cold redundancy requires a Client to reconnect to a backup Server after the initial Server has failed. Warm redundancy allows a Client to connect to multiple Servers, but only one Server will be providing values. In hot redundancy multiple Servers are able to provide data and a Client can connect to multiple Servers for the data.


Usage Considerations
Client must use failover mode to determine required actions to take when Server fails.


Conformance Testing

Client Server

Switch to a backup Server if failure is detected

Non-transparent redundancy