From the so-called fieldbus wars on, automations systems suffered from an increased heterogeneity . Since then solutions for the interconnection and integration of different communication technologies throughout the automation pyramid (see Figure 1.1) are still high in demand. However, past efforts tended to introduce additional abstraction layers above the field level, and direct interconnection between field protocols was seldom considered. Despite the fact that more and more critical infrastructure is incorporated into automation systems, only little effort is put into proper reliability mechanisms throughout existing integration solutions. Therefore, this thesis introduces a gateway solution targeting the problem of horizontal integration at the field level of the automation pyramid in a reliable way. A general applicable translation process between field networks has been advised. Field devices residing in one field network are mapped into another fieldbus by the means of a proposed information model. The information model has been inspired by modeling capabilities of well-established integration solutions like object linking and embedding (OLE) for process control (OPC) - unified architecture (OPC UA)  and open building information exchange (oBIX) . The reliability concept has been based on the replication of multiple gateway devices to form a redundant compound. Therefore, synchronization and end-to-end communication monitoring mechanisms are proposed. Synchronization tasks are performed via existing fieldbus connections, which obviates the need for a separate backbone link between individual gateway devices. Furthermore, the fault hypothesis of the redundant compound and the overall interconnected automation systems are stated and analyzed. Besides an analytic discussion of all fault scenarios and fault recovery processes, a proof-of-concept testbed for the technologies KNX and ZigBee has been developed to verify the results of the fault analysis. In conclusion, the described gateway approach has been proven to be a feasible and viable solution to the integration problem of different field level protocols. However, there are still tasks for future work, that have not been addressed by this thesis. This includes several management operations for the redundant gateway compound and more sophisticated mechanisms for fault handling.