Master Thesis - 2012
High speed and large capacity backbone network will be required for future high-quality multimedia services. For future networks, all optical Wavelength Division Multiplexing (WDM) networks have been expected as one of promising solutions. Recently, there are many researches about elastic optical networks which can flexibly exploit spectrum resources by selecting modulation format based on both demand size and optical reach.
In the elastic optical networks, appropriate spectrum separation (guard-band) is required between adjacent optical paths because spectrum resources are closely allocated in spectrum domain compared with the traditional WDM networks. This guard-band may cause the waste of spectrum resource. Traffic aggregation is one of the methods that reduce these spectrum resources utilizing for guard-band because an aggregated path is handled as one optical path on the intermediate nodes. Moreover, it is expected that the number of required transmitters is reduced. However, in a dynamic network scenario, various path set-up requests are randomly generated. Moreover, it is necessary to take the spectrum continuity constraints into account. Therefore, it is difficult to aggregate multiple paths efficiently.
In this thesis, on-demand path provisioning method with traffic aggregation in elastic optical networks is proposed. The proposed method aggregates multiple path set-up requests between the same source-destination pairs by allocating spectrum resources for these requests continuously in spectrum domain. For efficient path aggregation, a novel tentative resource reservation method which can adapt to the network condition flexibly is proposed. Higher spectrum resource utilization can be achieved with path aggregation.
Finally, effectiveness of the proposed method is confirmed through computer simulations. In particular, the proposed method can improve call-blocking probability about 90% at most. Furthermore, the proposed method can reduce the average number of required transmitters by about 50% compared with the no aggregation case.
