This specification defines an OPC UA AddressSpace to manage IO-Link Masters and their connected IO-Link Devices. To manage the IO-Link Devices without detailed knowledge of the device an IODD is needed to interpret the structures provided by the device. However, managing IODDs might be hard for servers running on small embedded devices with very limited resources. Therefore, this specification defines a server facet only providing the basic functionality without IODD interpretation (see section 15.4.1). This allows the implementation of such a facet with very limited resources, but requires that the client has knowledge about the device, either implemented in the client or implicitly by the user of the client.

The following section describes a solution to combine the benefit of an IODD interpretation and thus allowing full device access without detailed knowledge of the device by the user and the implementation of an OPC UA Server on very limited resources, by adding an aggregating server into the system providing the IODD based access.