In this paper we discuss the verification and validation of software architecture for system of systems. Software architecture plays a vital role in the systematic construction of large systems of systems; it defines the design space and provides a road map leading to the successful construction of system of systems that meet the functional and non-functional requirements. Moreover, a good architecture must allow the system of systems to evolve to meet new requirements due to change in mission. This paper introduces a mathematical model to tie the non-functional requirements of software systems to their architecture, and presents an approach to evaluate the quality of software architecture in light of meeting the requirements.