Each OPC UA Service request contains a string parameter that is used to carry an audit record id. A Client or any Server operating as a Client, such as an aggregating Server, can create a local audit log entry for a request that it submits. This parameter allows this Client to pass the identifier for this entry with the request. If this Server also maintains an audit log, it should include this id in its audit log entry that it writes. When this log is examined and that entry is found, the examiner will be able to relate it directly to the audit log entry created by the Client. This capability allows for traceability across audit logs within a system.