This Service Set can be separated into two groups: Services that are called by OPC UA Clients and Services that are invoked by OPC UA Servers. The FindServers and GetEndpoints Services that are called by OPC UA Clients may generate audit entries for failed Service invocations. The RegisterServer Service that is invoked by OPC UA Servers shall generate audit entries for all new registrations and for failed Service invocations. These audit entries shall include the Server URI, Server names, Discovery URIs and isOnline status. Audit entries should not be generated for RegisterServer invocation that does not cause changes to the registered Servers.