Research On Multicast Application Protection Strategies Based On QoP+QoS In WDM Networks

Sessions in optical networks have become more and more diversified with the rapid development and application of optical communication, especially the increasingly mature WDM technologies provide support for WDM networks to carry multicast sessions. Recently, multicast application has become dramatically wide, particularly the fusion of three networks has been changing with each passing day. However, the number of sessions influenced by network failures such as broken fibers also increases. So network survivability has become one of hot issues and core technologies in WDM networks. Furthermore, with increasingly enhancement of people’s consciousness to quality of protection (QoP) and quality of service (QoS), measuring and improving QoP and QoS comprehensively are significant to the development of multicast application.This thesis did in-depth researches on multicast application protection strategies in WDM networks in order to improve QoP and QoS. The structure and characteristics of WDM networks were summarized and the key technologies that support multicast and survivability in WDM networks were tracked and analysed. Based on those above, we did some innovative trials and designs as follows. Firstly, measurement index of QoP+QoS was studied. From the two aspects of qualitative and quantitative analyses, the qualitative cost function and quantitative QoP+QoS measurement were proposed respectively. Secondly, the classic MFBG recovery scheme was studied in order to realize combination of network protection scheme and recovery scheme. The VS_MFBG scheme was presented through optimizing and improving MFBG scheme from the viewpoint of virtual source in order to satisfy the sparse light splitting constraint. At last, the key design of SDP_QPS (Shared Disjoint Paths based on QoP+QoS) algorithm in the condition of sparse light splitting was accomplished. The innovation points of SDP_QPS were presented as follows. First, the measurement index of QoP+QoS was used for evaluation criterion. Second, the redundant links were cut off used by VS_MFBG scheme to save available resources. What is more, the self-sharing was referenced to calculate backup paths for work light-trees, which saved network resources further. Simulation results show that compared to SLPP (Source Leaf Path based Protection) under the same conditions, both QoP and QoS performances of SDP_QPS are better. Compared to OPP_SDP (Optimal Path Pair based Shared Disjoint Path), SDP_QPS has lower average number of wavelength, lower blocking probability but higher average end to end delay in networks with low traffic intensity. Compared to SDP_QPS based on qualitative cost function, SDP_QPS based on QoP+QoS measurement has a little difference on average number of wavelength, blocking probability and average end to end delay, which reveals that quantitative QoP+QoS measurement is more accurate than the qualitative one.