The network element of a system provides benefits of connectivity between disparate systems, including within coalitions. In order to understand the behaviours of networked systems it is not sufficient just to capture network lay downs or other technical architectures. Instead the people, processes and technology need to be understood, along with their respective interactions. A key challenge the military faces is how mission objectives can be related to the assets available (technical & human). This paper will describe how concepts in requirements engineering, augmented with system survivability techniques, can provide a practical means to achieve mission assurance and mission configurability. Requirements traceability is achieved using satisfaction arguments, while also capturing assumptions and constraints. Further, requirements description using controlled natural language is demonstrated as a first step in providing a machine traceable approach that would potentially allow for automated detection and response in the future, such as for network hardening. This work will develop a prototype toolset which can be trialled with defence users.