Research Of Routing Information Synchronization Technology And P2MP Algorithms In Multi-Layer And Multi-Domain Optical Networks

Optical communication technology is undergoing fast development and dramatic changes. With the rapid growth of network bandwidth capacity and switching technology, optical networks have gone through the progress from the synchronous digital hierarchy (SDH) networks to optical transport networks (OTN), and then automatically switched optical networks (ASON). The granularity in optical switching has increased to wavelength level, thus the IETF proposed the Wavelength Switched Optical Network (WSON) based on wavelength division multiplexing (WDM) technology. As the expanding scale of optical networks, multi-layer and multi-domain optical networks have become the trend of next generation networks.An information synchronization mechanism must be needed to support the path computation under different traffic engineering based strategies and constrains. In multi-layer and multi-domain optical networks, information synchronization becomes more complicated. Besides, as a typical application in routing technology, point-to-multi-point (P2MP) services calls for an optimization in paths computation and better quality of services for it has been more and more used in IPTV, video-on-demand, etc. In multi-domain networks, there are still difficulties in least-cost P2MP path computation.According to these issues, the paper has studied those key problems of the routing system in multi-layer and multi-domain intelligent optical networks. The main work and innovative contributions of this paper can be summarized as:Firstly, according to the demand of complexity and scalability of the optical network characteristics, a dual routing engine architecture in Multi-layer/Multi-domain/Multi-constraint optical networks (DREAM) is proposed, and an experiment platform based on DREAM and GMPLS/WSON/PCE standard is built which supports large-scale network. Secondly, design and implement the routing information synchronization module based on extended OSPF-TE protocol in DREAM platform, the module supports multi-domain path computation and multi-granularity and multi-channel topology information synchronization. Then the conformance, flooding convergence time and scalability of routing protocol have been tested by experiments.Thirdly, under the characteristics of P2MP computation in multi-domain GMPLS networks, a Multi-Domain Minimum-cost Path Heuristic (MDMPH) algorithm is proposed. Simulation experiments are conducted to analyze its performance to make a comparison with other algorithms, and the results show that the MDMPH algorithm computes less cost of P2MP trees.