Routing And Survivability Technologies In Intelligent Optical Networks

The large scale deployment of intelligent optical networks (ION) isessential to the development of optical communications technology.Scalability and survivability are two crucial requirements of intelligent opticalnetworks. ION can automatically establish dynamic traffic connections andeffectively configure network resources. And also multiple schemes for rapidrestoration are provided in ION. These incredible network functions arerealized due to intelligent control plane, including routing and survivabilitymechanisms. Specifically, this thesis focuses on routing and survivabilitytechnologies in ION. After systematical analysis of ION, we grasp the keyproblems of survivability and routing technology as to make deep andinnovative research. The main innovative results are in the following areas:1. Researches are made on topology information synchronization mechanismof hierarchical network. A notification mechanism of topology informationbased on speaker nodes and hierarchical routing algorithm are proposed,which realizes topology discovery, synchronization and routingcomputation in the hierarchical network. The size of routing load and linkstate database (LSDB) is rapidly decreased by using the proposednotification mechanism. Routing load (LSDB) of three-layer reduced by22% (41%) after applying the proposed mechanism and scalable problem isalso solved. The applicability of proposed mechanism and algorithms arevalidated by the experimentations. 2. Researches and developments are made on Hierarchical ASON Simulator (HOns) based on NS-2. The simulation platform is constructed to study the performance of large hierarchical network and is flexible without physical equipments.Many schems can be validated in the platform. This suggests that 2- and 3-layer are better suited for provisioning lower-blocking probability and chosen for ASON hierarchical networks. The conclusion of dividing into two or three layers in actual network is made.3. The role of parallel label-switched path in load balanced and constraint-based routing is investigated. A scheme named parallel-path-based bandwidth (PPBA) is proposed to make use of parallel LSPs in choosing a bandwidth constraint path. Numerical example shows the blocking probability is reduced to some extent when the number of feasible paths increases under hops on each path is the same in a single-path scheme. However, the reduction effect becomes unnoticeable when the number of feasible paths is more than three. There is a completely different behavior in PPBA scheme, every additional feasible path not only decreases the blocking probability significantly, but also greatly expands the range of acceptable bandwidth requirement. More parallel paths imply that each path has a smaller share of the traffic from a flow, thus the network as a whole can support higher traffic load. Under wavelength continuity constraint in a wavelength-routed network, the notion of cost based fairness routing is also studied according to Erlang B formulation in this section and a conclusion which the tariff for two-hop traffic should be set at more than twice that for the single-hop traffic if the former were to be guaranteed an identical threshold of service is made. The commonly held view that the customers whose information passes two hops should be charged less than twice the fare applicable to that for the single-hop traffic is not true.4. After extensive and systematical analysis of survivability of control plane, two schemes based on GMPLS protection and recovery mechanisms are proposed, one is solving failure of control plane, and another is solving state recovery of control plane. Meanwhile, optical service level agreement (SLA) technology is also investigated and mapping scheme and resilience provisioning of different services are proposed for the first time. These schemes are useful for plan the operator networks.5. Researches are made on M: N shared protection with revertive mode. A model of blocking probability is proposed and Engest formulation is deduced. Numerical results of calculatation by using the formulation are consistent with the actual networks, which are proved to be correct. The priority-aware 1:N protection strategy is also researched and it is shown that the high-priority connection protected using the priority-aware scheme is more available than the connections protected bye the classical shared scheme under 1:N shared protection mode.