Abstract: Battlefield communications systems should be simple, flexible and secure. The demand for managed Quality of Service (QoS) across a diverse range of services at varying security levels places significant strains on traditional trunk communications models. A more flexible link-layer switching architecture that can employ payload encryption is required. This paper proposes a change in the way that the trunk network should be viewed instead by seeing it as an unclassified common service infrastructure to carry all services. Additionally, more and more services are being sourced from the strategic network. Traditionally, the mobile and fixed architectures do not match, but a common approach to the underlying switching could solve this problem. This paper recommends Asynchronous Transfer Mode (ATM) as the protocol to meet these requirements.