Gateways - 101

This paper describes how gateways provide interoperability for the Department of Defense (DoD). At the same time these gateway interoperability solutions create problems including, amongst others: maintenance difficulties, certification issues, communications bottlenecks, single points of failure, impacts on communication network planning and monitoring. However, there are some significant opportunities created by introducing gateways. Gateways provide a near term option to make legacy systems interoperate. This paper discusses the pros and cons of gateways. Since legacy DoD systems will not be removed from the field at once, a translation requirement will remain until all systems use the future common infrastructure and a common information representation format. Because the term gateway is overloaded, the paper recommends a definition for a communications gateway and some associated terms. We address the benefits and drawbacks of commonly used gateway approaches and provide a short history of translators and gateways. One of the greatest challenges is creation and certification of the translation and forwarding rules. Finally, we address recommendations for future gateways that utilize a fully layered architecture.