Translucent optical networks use sparsely located regenerator nodes to increase the optical reach, otherwise limited by the physical layer impairments. Routing in translucent networks often causes the lightpath to traverse a fiber more than once, requiring the use of multiple wavelengths on a fiber for the same lightpath. Most of the routing and wavelength assignment (RWA) algorithms for static demand in translucent networks (termed static RWA) require loop-free routes for shortest path routing and also are agnostic to traffic load. In this paper, we address the problem of static RWA in translucent networks without using physical layer information and show how to route lightpaths on paths with a loop (i.e., not a simple path). We propose integer linear programming formulation to get the exact solutions to the static RWA problem. This work is the first one to optimally solve the static RWA problem for non-simple paths, providing the lower bound on the number of wavelengths and regeneration needed for static lightpath establishment when regeneration facilities are limited. We propose a heuristic algorithm based on the concept of Wardrop equilibrium, to adaptively equalize the mean delay along all the lightpath routes from source to destination. The proposed heuristic can not only accommodate the correlation between feasible lightpath routes but also account for the fact that alternate routes correspond to different levels of choice randomness. Wavelength assignment is done using graph coloring with branch-and-price method. Numerical results demonstrate that the proposed heuristic reduces the number of regenerators and wavelengths required to satisfy a given demand.

中文翻译：

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半透明光网络中静态需求的光路路由和波长分配

半透明的光网络使用稀疏放置的再生器节点来增加光覆盖范围，否则会受到物理层损害的限制。半透明网络中的路由通常会导致光路不止一次穿越光纤，因此对于同一光路，需要在光纤上使用多个波长。对于半透明网络中的静态需求（称为静态RWA），大多数路由和波长分配（RWA）算法都需要无环路由以实现最短路径路由，并且与流量负载无关。在本文中，我们在不使用物理层信息的情况下解决了半透明网络中的静态RWA问题，并展示了如何在具有环路的路径（即非简单路径）上路由光路。我们提出整数线性规划公式以获取静态RWA问题的精确解决方案。这项工作是第一个针对非简单路径最佳解决静态RWA问题的工作，它在再生设施有限的情况下，为建立静态光路提供了波长和再生所需的下限。我们提出了一种基于Wardrop平衡概念的启发式算法，以自适应地均衡从源到目的地的所有光路路径上的平均延迟。所提出的启发式方法不仅可以适应可行的光路路径之间的相关性，而且可以解释以下事实：备用路径对应于不同级别的选择随机性。波长分配是使用带有分支和价格的图形着色完成的方法。数值结果表明，所提出的启发式方法减少了满足给定需求所需的再生器数量和波长。