If the Server is to be part of a Client trace, the Client passes the SpanContextDataType structure to a Server.

The SpanContextDataType Structure, defined in Table 7, is passed in the RequestHeader of any OPC UA Service call. The SpanContextDataType is transported with the AdditionalParametersType in the AdditionalHeader field of the RequestHeader (see OPC 10000-4). The Key for the parameter is “SpanContext” and the Value is the SpanContextDataType Structure.

If a Server receives the optional AdditionalHeader, it uses the provided SpanConextDataType Structure when generating any LogRecords that are generated related to the Service invocation that provided the AdditionalHeader. It is possible that lower level functionality that is invoked as part of the Service call, may not have access to the provided AdditionalHeader, in which case it maybe omitted.

Inside the Server, the SpanId from the RequestHeader is used as ParentId for the LogContext structure defined in Table 9.