Novel Elastic Optical Network Embedding Using Re-Optimized VCAT Framework Accompanied by Hitless PPSM Function

Abstract

The elastic optical network (EON) provides fine-grained and orthogonal frequency slots for establishing the connection that will realize high-rate data transmission among data centers (DCs). With the implementation of cloud DCs (CDCs) and EON virtualization, achieving EON embedding (EONE) is essential, which includes two components: node mapping from the virtual machine to the CDC and link mapping from the virtual lightpath to fiber link(s). In particular, the link mapping must satisfy some rigid constraints in terms of spectrum continuity, consistency, and nonoverlapping, which may create spectrum fragments over fiber links. Thus, in this paper, we reoptimize the virtual concatenation (VCAT) framework accompanied by the hitless push-pull spectrum movement (PPSM) function when the common link mapping fails. Our design framework integrates spectrum movement with inverse multiplexing such that more EONE requests can be satisfied by performing effective spectrum defragmentation. We also optimize the number of subbands with a constrained buffer size to compensate the differential delay at the receiving end. The problem is formulated using the relaxed integer linear programming (ILP) model, and the corresponding heuristic tailored to four different service-sorting strategies is also designed. The simulation results verify the superiority of our method in terms of increasing the spectrum efficiency and reducing the blocking rate of EONE requests. This paper is the first work to focus on designing a reoptimized VCAT framework accompanied by the hitless PPSM function for the EONE that includes both node and link mapping processes rather than a simple spectrum defragmentation.