Interworking Between Optical Burst Switching Networks And Optical Circuit Switching Networks

Looking back into the technical history of the optical networks, it can be clearly seen that the development of technolodgies was driven by the development of diverse traffic demands. After the first generation of static point-to-point optical networks and the second generation of dynamic OCS networks, the next generation optical network is imminent to meet the various demands of ever-developing services and traffics.The next generation optical network is considered to be a polymorphous, agile, intelligent, transparent and reliable optical network capable to provide various QoS classified services to the traffics with diverse switching and transmission requirements. Considering above mentioned situation, this paper further investigated the hierarchical multi-domain OBS/OCS network with transparent end-to-end optical connections (i.e. the OBS/GMPLS network) based on the extensively-studied OBS and OCS network technologies. The prototype, feasibility, survivability and support of real traffics of the OBS/GMPLS network were intensively investigated and experimentally evaluated by using an OBS/GMPLS network testbed. The major contributions of this paper can be summarized as follows:1) To address the problems of low resource utilization and lack of end-to-end transparency in the current OCS core networks, the overlay-based multilayer OBS/GMPLS interworking network architecture was proposed and constructed by deploying a GMPLS-controlled transparent OCS network as the transport core, while distributing multiple small-scale OBS networks around as the edge to access the traffics. The OBS networks were deployed at the edge to extend the transparent optical connectivity to be closer to the end users, while the aggregation nature of OBS could also enhance the resource utilization in the core OCS network. In order to implement the overlay-based multilayer transparent OBS/GMPLS network, the key issues such as the Group-LSP, the wavelength continuity constrains, the dynamic inter-domain routing, the dynamic offset time scheme as well as the traffic driven provisioning of the end-to-end transparent wavelength connections were intensively investigated in this paper. By constructing an OBS/GMPLS network testbed and conducting serious of experiments on the testbed, the feasibility and effectiveness of the proposed OBS/GMPLS interworking architecture were evidently verified.2) Considering the survivability requirements of the transparent OBS/GMPLS network, the specific protection and restoration schemes were proposed in the OBS domain, and the dynamic QoS classified survivability mechanisms were extended in the GMPLS domain based on the original protection/restoration schemes. Then the integrated dynamic protection/restoration schemes supporting QoS were proposed in the OBS/GMPLS interworking network. Moreover, the interworking interface, signaling extensions as well as the fault detection schemes were further investigated to support the survivability schemes. In order to verify the feasibility and applicability of the proposed schemes, several experiments were conducted on the OBS/GMPLS network testbed. At last, the TCP transmission over the protected OBS/GMPLS network under different link failure situations were experimentally evaluated, and certain suggestions on the network parameters and survivability schemes were also made to benefit the performances of OBS/GMPLS network when transmitting real TCP traffics.3) Streaming media traffics are considered to be the major traffic types which will occupy most of the future network bandwidth volumes. While on the other hand, the TDM equipments and traffics are the main existing technologies in nowadays networks. Considering this situation, this paper investigated the support to these two kinds of traffics in OBS/GMPLS networks. In case of streaming media traffics, the QoS classified survivability schemes to protect different class of stream media with various bit rates were evaluated by introducing two parameters defined as the Delay Factor (DF) and the number of IP packet loss per link failure. According to the experimental results, the priority of the four survivability schemes to different class of traffics can be summarized as a suggestion to the network manager to enhance the intelligence of the network. With respect to the TDM traffics, the specific resource reservation mechanisms and signaling extensions were proposed and implemented on the OBS/GMPLS network testbed. Finally, the successful transmission and QoS provision of TDM traffics over the testbed verified that the proposed schemes could effectively reserve resources and guarantee QoS for TDM traffics.