To a Client the transparent RedundantServerSet appears as if it is just a single Server and the Client has no Failover actions to perform. All Servers in the RedundantServerSet have an identical ServerUri and an identical EndpointUrl.

Figure 26 shows a typical transparent Redundancy setup.


Figure 26 – Transparent Redundancy setup example

For transparent Redundancy, OPC UA provides data structures to allow Clients to identify which Servers are in the RedundantServerSet, the ServiceLevel of each Server, and which Server is currently responsible for the Client Session. This information is specified in TransparentRedundancyType ObjectType defined in OPC 10000-5. Since the ServerUri is identical for all Servers in the RedundantServerSet, the Servers are identified with a ServerId contained in the information provided in the TransparentRedundancyType Object.

In transparent Redundancy, a Client is not able to control which physical Server it actually connects to. Failover is controlled by the RedundantServerSet and a Client is also not able to actively Failover to another Server in the RedundantServerSet.