Current approaches in the design of ring-based optical networks

We discuss the problem of designing minimum-cost transport networks using path-protection and shared-protection optical rings. A description of the multi-ring network design problem is provided along with a survey of relevant prior work. We then propose three integer programming formulations for the multi-ring network design problem and discuss their comparative features and drawbacks with reference to some preliminary results obtained. We conclude with a discussion of future work in this area.