# The Future of Factories: Different Trends
## 5 Comparison between Cmfg and vF
The described proposal enables interoperability over the three levels: (i) data transfer protocol, (ii) semantic of data, (iii) data presentation. Those solutions are based on the adoption of standard IT protocols like HTTP for data transfer, ontologies for providing semantic to the data (Resource Description Framework (RDF), OWL), and standard data format as the JSON format for data representation. **Service interoperability**. In a virtual factory, a collaborative process includes the composition and integration of existing manufacturing services supported by technologies from the service-oriented computing (SOA) [43]. In cloud manufacturing, each manufacturing asset is virtualized via a virtual resource layer and deployed as a service through a service-oriented layer, composing the cloud manufacturing architecture. For example, for virtual enterprises and collaborative networks, cloud manufacturing supports different forms of collaboration, such as loose coupling and tight coupling, and builds different forms of alliances through its highly flexible cloud architecture, as mentioned before. Cloud manufacturing enables the integration of decentralized social manufacturing assets to achieve high levels of sharing and collaboration. In cloud manufacturing, enterprises perform service development and provide manufacturing services to each other. It can be seen that the concept of cloud manufacturing and service-oriented manufacturing is completely consistent. Therefore, integration of cloud manufacturing services relies on the adoption of service-oriented architecture as in a virtual factory. As an example, we report the work of [44], in which authors propose a service-oriented architecture based on a service broker to orchestrate services of multiple heterogeneous clouds. **Operational Roles**. The Cmfg paradigm differentiates operational roles, such as resource consumers, resources providers, and cloud operators. Although these roles are immutable in a standard cloud environment, as pointed out in the previous section, cloud manufacturing opens up new forms of collaborative models in which operational roles, as well as sharing policies, are interchangeable. Therefore, the roles of the actors in a multiple cloud collaborative environment need to be further studied to support a dynamic form of collaborations, flexible sharing policies, as well as diverse pricing models for each manufacturing asset. At the same time, the human role is taking into consideration during the design of a virtual factory [45]; in particular, the parties involved in a service-oriented virtual factory are defined as [43]: service resource, service provider, service consumer, and service broker. These roles, respectively, identify the parties which offer physical services, the consumer of these services, and the owner who controls and governs the virtual factory. Therefore, although the virtual factory roles are coherent with the ones defined in the Cmfg, as proposed in the Cloud, deployment models, as well as pricing models, need to be further examined to enable a flexible collaboration between virtual factories. **Simulation and Optimization**. From a virtual factory as an IT platform perspective, the potential is extended to plan, simulate, and control the shop floor to assess the future impact of production and maintenance planning decisions [46]. Similarly, in a cloud environment, cloud-based services monitor the production planning and control the discrete manufacturing environment (i.e., machine availability monitoring and collaborative and adaptive process planning [47], simultaneous shop scheduling, and material planning [48]).