This draft first briefly discusses the unique architecture of mesh- ring networks. Guo et al. In the past several years, a large number of optical rings are deployed by telecomm operators. One of advantages for using optical rings is their simplified and robust mechanism for failure protection. Ring topology has some drawbacks, which motivates the emergence of optical mesh networks.
Optical meshes provide better connection flexi- bility and network resource utilization.
The management complexities for meshed networks however are higher. We foresee that the networks consisting of hybrid rings and meshes, called mesh-rings, are of particular importance. This is because the migration from rings to meshes will be a gradual process. Furthermore, the merit debates between rings and meshes are not expected to be conclusive. Mesh-ring networks can be formed by either embedding rings into meshes or by connecting rings with meshes.