Considering convergence of vast and different technologies in new generation networks, the required quality of service is the key success factor. The site implementation according to special benchmarking (TPC-W), to achieve the acceptable service performance may be offered in a cost effective manner, is very complicated. In this paper a mathematical method will be introduced to help providers to make informed decisions with respect of right level of resources (number and server capacity, number and power of CPUs, and amount of permanent and temporary memory). The numerical results show that the new formulation confirms the results of e-commerce site emulation in an acceptable level.