Joint Banding-Node Placement and Resource Allocation for Multi-Granular Elastic Optical Networks

Abstract

The rapid growth of Internet traffic has caused researchers continue to seek new ways to increase fiber bandwidth and spectrum utilization efficiency through elastic optical networking (EON). The advantage of EON comes from the fine-grained grid, which allows traffic demands to be better matched through a flexible allocation of fiber bandwidth. To further increase capacity, multiple fibers per link will be desired. Conventional optical crossconnects (OXCs) that use wavelength selective switches (WSSs) to switch the slots of a lightpath from input fibers to output fibers do not scale well. A more scalable and cost-effective node architecture called a flexible wavebanding crossconnect (FLEX) has been proposed recently. The FLEX architecture considerably reduces the cost of the crossconnect while introducing a small performance penalty in the form of reduced switching flexibility. In order to alleviate the limited switching capability, a cost-function-pluggable auxiliary layered-graph framework has also been proposed recently to solve the routing, fiber, waveband, and spectrum assignment (RFBSA) problem in multi-fiber EON with FLEX nodes. In this paper, we address the following problem. Given a budget in terms of the number of available WSSs for the network, determine the number and placements of FLEX nodes, and solve the RFBSA problem jointly in order to optimize network performance. We present an integer linear programming formulation, and propose a heuristic algorithm to solve this joint problem. The results show that our heuristic algorithm achieves good network performance, as measured by the average maximum spectrum usage (MSU), while saving significant hardware costs.