Research On Routing And Survivability Technologies In Distributed Optical Networks

As the key technologies of achieving the efficient service transmission in communications network, routing and survivability technologies are essential to the network performance. As the broadband becomes the main theme of each country in the future, the researches about broadband network become common. In the aspect of broadband backbone network, the dissertation mainly focused on the routing and survivability technologies in distributed optical networks as the centralized optical networks gradually develop to the distributed optical networks, while in the aspect of broadband access network, the dissertation mainly focused on the routing and survivability technologies in distributed radio over fiber (RoF) networks as the centralized RoF networks gradually develop to the distributed RoF networks. To conclude, the dissertation mainly focused on the routing and survivability technologies in distributed optical networks and RoF networks, and studied corresponding routing and survivability schemes and algorithms aiming to the different characteristics of backbone networks and access networks and gained a number of innovative research achievements, and the concrete research contents are as follows:(1) Research on quality of service (QoS) based routing algorithm in distributed optical networks. Both aspects are included:the first is researching on multi-constrained routing; the second is researching on differentiated service routing. In the first aspect, a multi-constrained routing algorithm which can achieve a better tradeoff between algorithm complexity and algorithm accuracy is proposed aiming to the drawback of high algorithm complexity or low algorithm accuracy in existing multi-constrained routing algorithms. The proposed algorithm effectively reduces the network blocking probability and in the meantime achieves similar complexity with the others. In the second aspect, a differentiated service routing algorithm which can fully make use of the capacity of services themselves in optical packet switching (OPS) networks is proposed aiming to the drawback of existing service differentiation schemes which can not use the capacity of services themselves. The proposed algorithm does not occupy the additional network resources, thus effectively increasing the resource utilization ratio (RUR).(2) Research on wavelength optimization routing algorithm in distributed optical networks. An algorithm which is optimized before routing computation is proposed aiming at the current situation of exsiting algorithms which are optimized after each request is computed. The proposed algorithm forms a new link cost of considering the wavelength usage before routing computation and updates the new cost after each request is computed, thus effectively increasing the RUR.(3) Research on fast restoration scheme in distributed optical networks. Both aspects are included:the first is researching on fast restoration scheme aiming at the case of single failure; the second is researching on fast restoration scheme aiming at the case of multiple failures. In the first aspect, a fast parallel restoration scheme is proposed aiming at the problem of the long restoration time among the existing restoration algorithms. The proposed scheme effectively reduces the connection setup time. In the second aspect, a local node based multi-failure restoration mechanism is proposed aiming at the lack of multi-failure restoration scheme in optical multicast. The proposed restoration mechanism effectively reduces the restoration time and increases the restoration rate.(4) Research on joint routing algorithm and balanced restoration scheme in distributed RoF networks. A novel joint routing algorithm which simultaneously considers wire networks and wireless networks is proposed aiming at the local optimum problem of single routing computation of wire networks and wireless networks in RoF networks, and the global optimum route is obtained; A traffic partition restoration scheme is proposed aiming at the problem of the low RUR in the existing survivability schemes of RoF networks, and the restoration ratio is increased applying the proposed scheme.