Cost-optimal VPN based VoIP network design

This work addresses the design of cost-optimal VoIP networks. In our model the whole VoIP network is divided into two logical components: the access network and the transport network. The access network consists of the VoIP end-points that connect to the transport network through edge routers serving as gateways. Since more edge routers may be available for a given VoIP node, one task of the design process is to assign a particular edge router to every VoIP node. The edge routers have to be connected in such a way that security and availability can be assured for the VoIP traffic. One obvious approach to fulfilling these requirements is to define a VPN, which is assumed throughout the paper. Supposing large volume of VoIP traffic the cost of the VPN can be significant. Thus the other task of VoIP network design is to specify the transport VPN in the most economical way. These two tasks of VoIP network design can be solved separately using existing methods. Nevertheless, the VoIP region specification influences the cost of the final solution to a great extent. Therefore, in This work we propose a novel solution in which the edge router assignment takes the objective function of VPN specification into consideration. Moreover, a numerical analysis is provided with the help of simulations.