The future Internet evolution is driven by applications that require simultaneous real-time access to multiple heterogeneous IT resources interconnected by high-speed optical networks. In this paper, we propose a novel service-oriented resource orchestration model based on the optimization of heterogeneous IT and network resources owned by different Infrastructure Providers (InPs). The proposed model aims to achieve a global optimum from both the end-users' and InPs' point of view across different administrative domains. An integer linear program (ILP) is formulated to obtain optimal results that maximizes the number of accepted requests while minimizing resource usage. It is compared against a co-scheduling ILP model, whose objective is to maximize the number of accepted requests only. Finally, we propose a heuristic solution for scalability. Its performance is compared against (i) our proposed ILP (ii) a co-scheduling heuristic that aim to maximize number of accepted requests only and (iii) an algorithm that does not take into account cross-domain optimizations.