Research Of Key Technologies On Resource Optimization And Constraint-Based Routing For Optical Transport Networks

The rapid growth of Internet and other data applications (such as digital video broadcasting, cloud computation, cloud storage, and so on) has become a huge challenge for the optical transport networks. Optical transport networks should be able to carry the full-service, including voice and data services, multimedia services and other business carrying requirements, providing flexible, efficient and reliable bandwidth. OTN and PTN technologies, which are replacing SDH and DWDM, are the inevitable evolution trends. Although data transport can be solved by OTN and PTN, there is still a validity requirement. Under the driven of the validity requirement, there are still a series of problems in optical transport networks, such as service complexity, routing cooperation and network efficiency. To solve these problems, this paper mainly researches on the key technologies in optical transport networks, especially the problem of routing and resource optimization, with the support by the project of the national high-tech research and development program "next generation optical network standards, testing and networking application". A number of innovative research achievements have been gained. The main contribution and innovation of this dissertation are described as follows.Firstly, in order to solve the unbalance problem caused by the structure of the OTN node, an OTN numeric model is proposed to analyze the structure constraints problem of the OTN node. Based on the numeric model above, three multi-layer traffic grooming algorithms (OC-DKI, OC-DIK and OC-DIKP) are also proposed, in which the OTN capacity constraint is taken into account. Furthermore, five wavelength assignment algorithms are also proposed. Numeric results show that OC-DKI and M&R/R&M algorithms have better performance.Secondly, based on three multi-layer traffic grooming algorithms proposed above, LIU placement problem in the backbone OTN network is simulated and analyzed. Numeric results show that the best LIU placement ratio is 60%-70%. Furthermore, two heuristic algorithms called MBPO and LAO are proposed for solving the cross-connects capacity management problem. All simulations have been done on a simulation platform implemented using disperse event simulation tool OMNeT++, and the proposed algorithm has been implemented using Perl language. Numeric results showed that the MBPO algorithm has better performance than the LAO algorithm, and the resultant scheme enables the operators to decrease the CAPEX.Thirdly, QoS sensitive routing is a very important component of traffic engineering in DiffServ MPLS-TP networks. Based on studies of characteristics of packet scheduling algorithms and the problem of unfairness when QoS routing does not consider the mix of traffic classes, a new routing scheme STE-QOSPF-Mix, which takes the reserved bandwidth supported WFQ algorithm into account, is proposed. To determine the QoS route for a flow request, STE-QOSPF-Mix considers the effective available bandwidth instead of residual bandwidth of the path, which is more suitable in DiffServ MPLS-TP networks. The simulation results show that our proposed STE-QOSPF-Mix scheme outperforms other schemes in terms of end to end delay.