The elastic optical networks, a.k.a., flexgrid networks, have flexible spectrum allocation. Such flexibility is possible due to the division of the spectrum into narrow frequency slots and the use of bandwidth-variable transponders. This enables the demand, in terms of band request, to be contiguously allocated starting from any available slot of the spectrum. In this context, the RSA (Routing and Spectrum Allocation) was proposed as an offline optimization problem of allocating the optical transmission resources in order to meet a predefined set of demands. This work deals with the capacitated version of the RSA problem. To solve it, we develop a multi-commodity flow formulation based on ILP (Integer Linear Programming) and a load balancing procedure that generate promising paths for an ILP formulation from the literature. Extensive computational experiments show that the proposed solution approaches are capable of obtaining high quality solutions on a variety of scenarios.

弹性光网络（也称为弹性网格网络）具有灵活的频谱分配。由于频谱被划分为狭窄的频率时隙以及使用带宽可变的转发器，因此这种灵活性是可能的。这使得就频带请求而言，从频谱的任何可用时隙开始连续分配需求。在这种情况下，提出了RSA（路由和频谱分配）作为分配光传输资源以满足预定义需求的离线优化问题。这项工作处理的是RSA问题的简化版本。为了解决这个问题，我们开发了一种基于ILP（整数线性规划）的多商品流程公式化和一种负载平衡程序，该程序从文献中为ILP公式化产生了有希望的路径。