Abstract: Synchronous optical network (SONET) self-healing ring architecture is used for designing more survivable and economical broadband networks. Virtual path (VP)-based asynchronous transfer mode (ATM) technology is being introduced into SONET rings as a means of reducing costs by using its non-hierarchical path multiplexing and flexible demand arrangement. This paper describes an algorithm for determining the feasibility of SONET/ATM rings over a diverse protection (DP) architecture when deploying the rings in the network. It is assumed that the ATM/add-drop multiplexer (ADM) for the VP-based ATM rings can be built from SONET ADM by installing the ATM STS-3c line cards in place of the STS-3 termination cards. Hence, the algorithm is applicable to both SONET ring and VP-based ATM ring architectures. By using reference network databases the simulation results are also provided. The cost depends on amount of traffic, demand routing, size of network and network connectivity. In our simulation results, we found that the cost savings over DPs ranged from 2.6% to 19.9%. It is recommended that network planners and network analysts carefully evaluate where to deploy SONET/ATM rings for more survivable and economical broadband networks.