Novel control plane framework and protocol extensions for Spectrum-Efficient Optical Transport Networks

Spectrum-Efficient Optical Transport Networks (SE-OTN), the most important character of which is high spectrum efficiency due to flexible grid, have attracted much attention recently. However, it cannot be employed for practical use since most of the related protocols are immature. This paper mainly focuses on the framework and protocol extensions for the control plane of SE-OTN. A novel control plane framework is designed combining the advantages of Generalized Multi-Protocol Label Switching (GMPLS) and Path Computation Element (PCE), and several routing and spectrum assignment (RSA) models are built. Furthermore, motivation and extension solutions for Open Shortest Path First-Traffic Engineering (OSPF-TE), Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE), and PCE Protocol (PCEP) are proposed based on this framework. An experimental testbed of large-scale spectrum-efficient optical networks with the capability of supporting 1000 GMPLS-based control nodes has been built to validate the performance of the protocols and algorithms, and some numeric results and analysis are given finally. Numeric results show that our proposed Centralized Routing and Centralized Spectrum Assignment (CR+CSA) model has better performance than Centralized Routing and Distributed Spectrum Assignment (CR+DSA) and Distributed Routing and Distributed Spectrum Assignment (DR+DSA), and spectrum defragmentation algorithm based on spectrum compactness can get good performance in the CR+CSA model.