The Technology Of Spectrum Defragment Ation In The Flexible Grid Optical Networks

With the size of network increasing, the demand for information is growing rapidly and high-capacity transmission network is also facing great challenges because of more and more service. However, WDM (Wavelength Division Multiplex) optical network cannot achieve the service of super-channel and mixing rate. So it drives the generation and development of the next generation of optical networks-flexible grid optical networks.Due to the presence of spectral continuity constraint in the flexible grid optical network, the spectrum fragmentation is more prominent, which not only reduces the spectrum utilization, but also increases the rate of traffic blocking. To solve the problem of spectrum debris, we centralized spectrum debris, in order to make use of the free spectrum resources as possible as we can.This thesis explores the spectrum defragmentation in the flexible grid optical networks and creatively put forward the new view in the next three research direction.First, the thesis puts forward a trigger mechanism for the spectrum defragmentation. By using a method of counting the spectrum resource status of network, it can make sure whether the network needs spectrum defragmentation or not, according to the used and idle states of the spectrum resources. At last compare the results under different threshold values.Second, the thesis proposes a defragmentation algorithm based on the modulation formats, and extends the PCEP. By summarizing abroad algorithm of spectrum defragmentation and knowing that business modulation formats can be changed in a flexible grid optical network, the thesis proposes a defragmentation algorithm. And it is compared with the greedy defragmentation algorithm, the result shows that the former is better than the latter on the blocking rate and spectrum utilization. The thesis extends the PCEP in three aspects, which are the new character of the flexible grid optical network, spectrum defragmentation and multicast, to promote the standardization process of flexible grid optical network.Third, the thesis raises an evaluation mechanism of the algorithm of spectrum defragmentation. Based on the cost-effectiveness, it proposes a Q value which is used to measuring the affectivity of spectrum defragmentation. The evaluation mechanism can be used to find the best algorithm of spectrum defragmentation.