With the proliferation of data networks, Voice over IP (VoIP) offers many attractions, not least among the Air Traffic Management (ATM) community. A recent interoperability testing event has helped to demonstrate the feasibility and robustness of VoIP for ATM, thus bringing the technology one step closer to deployment within the framework of the Single European Sky (SES) initiative.
Interoperability between different Voice Communication Systems (VCS) and different Ground Radio Stations (GRS) is key to the success and safety of this technology. The second EUROCAE VoIP for ATM Plugtests interoperability event organised by ETSI at its headquarters in Sophia Antipolis, France (25th March - 3rd April 2009) has confirmed the robustness of the EUROCAE interworking specification (ED 137) for VCS and GRS. 11 equipment manufacturers participated in the event, as well as two European Air Navigation Service Providers (ANSPs) attending as observers. ANSPs are typical clients for the products and services tested at this event. This event built on the first VoIP ATM Plugtests event held in April 2008. In order to verify correct functionality over a Local Area Network this second event involved the more complex "Stage 2" tests which covered the remaining mandatory SIP (Session Initiation Protocol) telephone and radio interface interoperability tests defined by EUROCAE draft specification ED-139. Guy Potiron, Chairman of EUROCAE Working Group 67 (responsible for the specifications for VoIP for ATM), and a representative of DSNA, one of the ANSPs present at the event, remarked: The results of this second EUROCAE Plugtests Interoperability event on VoIP for ATM have demonstrated the advanced maturity of the very recently approved EUROCAE documents (EDs), allowing interoperability between ATM VoIP components (VCS and GRS). The event has also confirmed the efficiency of the ETSI Plugtests processes, means, tools and personnel for organizing and performing these types of tests, the good maturity of the draft developments by European ATM VoIP suppliers, and the excellent co-operation between all the ATM VoIP stakeholders (suppliers, ANSPs, ETSI, EUROCAE, and Eurocontrol)." Mr Potiron added: "This event has confirmed my belief that it is wholly feasible to develop robust Air Traffic Service (ATS) VoIP standards at the European (SES) and International (ICAO) levels within two years and to start ATS VoIP implementation at the beginning of the next decade. The numerous test scenarios performed by the suppliers participating in the event demonstrated a very high degree of interoperability. These excellent results show that the VoIP call types and the wide range of ATS features specified by the EUROCAE document have now been developed and implemented by the main European Voice Communication Systems and radio systems suppliers. The high level of interoperability achieved will lead to deployment of ATM VoIP VCS and GRS by Air Navigation Service Providers in the very near future for operational use within the framework of the Single European Sky initiative. Hansjoerg Seipp of DFS Deutsche Flugsicherung, another of the ANSPs observing the interoperability event, said: This Plugtests event has extensively checked the specifications versus the implementations and we can once again show the high quality of the EUROCAE interoperability standards. With 11 manufacturers present at the event we have given valuable feedback to the community and demonstrated that the specified features can be implemented. The high degree of performance showed the concern, enthusiasm and engagement of the industry in this important area. A follow-up event is planned for September 2009, which will concentrate on ATM Gateways.