# The Role of Multi-Agent Systems in Realizing Asset Administration Shell Type 3
## 4 Agent-Based Reference Model for Realizing AAS Type 3
### Communication Based on VDI/VDE 2193 and FIPA Standards  
The agent communication capability is another key feature for AAS Type 3 solutions and is essential for enabling seamless, real-time information exchange and collaboration among distributed assets. This capability allows AASs to negotiate, coordinate tasks in a distributed manner, and share knowledge/information, enhancing the flexibility,  
Figure 7: Results of the recommended interface practices for the inspection gauge. reconfigurability, and responsiveness of I4.0 systems. In this context, the adoption of proper standards, such as the I4.0 language, as specified in the VDI/VDE 2193 standards, should be considered to enable interactions between AAS Type 3 solutions. These standards define both the vocabulary and message structures (VDI/VDE 2193-1) [42], as well as the interaction protocols (VDI/VDE 2193-2) [43], which can be used as the basis for agent communication design. The importance of adopting the I4.0 language as the official communication standard rather than relying on more general agent-specific standards such as FIPA lies in two main reasons: (i) its direct alignment with the definitions and requirements of AAS Type 3, and (ii) although this work employs an agent-based approach to support AAS Type 3 functionalities, it must still be recognized and treated as an AAS Type 3 solution. Therefore, to ensure communication interoperability, it is essential that all solutions conform to common vocabulary, message structure, and interaction protocols, especially considering that other AAS Type 3 implementations may be based on different architectural or technological approaches. Nonetheless, by adopting the I4.0 language as a shared communication standard, these heterogeneous solutions can still interoperate and collaborate effectively, regardless of their internal implementation choices. Although the I4.0 language is recommended for enabling I4.0-compliant interactions and has a broad scope, the current VDI/VDE 2193-2 standard specifies only the bidding protocol (based on the classic contract net protocol). This limitation restricts solutions that require a wider variety of interaction patterns to support diverse collaboration strategies among AAS Type 3 instances. In this context, several interaction protocols already defined in the FIPA agent communication language (ACL) standards could be adapted to align with the guidelines of the I4.0 language. This transition from FIPA-based interaction protocols to I4.0 language-based protocols is expected to be straightforward, given the strong similarity and compatibility between the two standards. In fact, the VDI/VDE 2193 standards are inspired by the FIPA specifications. For instance, Table 5 maps the parameters of the FIPA ACL message structure to the corresponding elements defined in VDI/VDE 2193-1, demonstrating their equivalence. Furthermore, the communicative acts defined in both standards exhibit only minimal differences, primarily in nomenclature. For a comparison, see [42; 44]. In this context, future versions or extensions of the VDI/VDE 2193 standards could formally standardize the mapping between FIPA protocols and the I4.0 language, ensuring their official integration and enabling consistent, interoperable communication. Some examples of candidate FIPA interaction protocols are as follows: request interaction protocol [45], subscribe interaction protocol [46], propose interaction protocol [47], query interaction protocol [48], and request when interaction protocol [49]. While such formal mappings would facilitate development and promote interoperability, it is important to note that the proposed reference model remains implementable using the current FIPA and VDI/VDE 2193 standards independently. However, this may require manual integration efforts, which could limit interoperability and increase development complexity. Another crucial aspect of communication is vocabulary, which relates to the semantic dimension of information exchange.