Study On The Several Key Technologies In Optical Burst Switching Network

Optical Burst Switching network separates Burst Data Packets and control channel to realize the transferring in all optical manners. It conquers the limit of electrical processing in the electric domain, and improves the efficiency of whole network. OBS network is considered as one of the most promising solutions for the vast-bandwidth and high-speed switching network in the future. The current optical switching can be divided into three types: 1) Optical Circuit Switching; 2) Optical Packet Switching and 3) Optical Burst Switching. OBS has better bandwidth utilization compared with OCS. Meanwhile compared with OPS, OBS avoid the problem of no optical buffer, and reduce the cost of network construction. The study on key technologies in OBS networks will become the important step in the process of deploying the OBS networks. The design of OXC in core node and assembly strategy in edge node are discussed and analyzed in this paper. According to build OBS simulation platform based on NS-2 called OBS-NP, different key technologies in OBS network can be compared and analyzed.The main contributions and numerical results of the dissertation are as follows:1. Proposed an assembly module entitled OBS-Ethernet self-tuning assembly module for the edge node in optical burst switching networks. The traffic detection queue is included in the designed module by whose output is used to choose the suitable assembly time threshold. Moreover, the control curve is adjusted by the feedback of the BDP length. Simulation results demonstrate that the OBS-Ethernet self-tuning assembly module has less average assembly delay when the traffic bursty is strong compared with MBMAP assembly module. In addition, the assembly time threshold in the OBS-Ethernet self-tuning assembly module can be adjusted according to the network traffic, which is different from MBMAP assembly strategy whose assembly thresholds are static.2. In order to improve the assembly performances of Optical Burst Switching (OBS) networks, by analyzing the shortcomings of existing assembly strategies, a novel adaptive assembly strategy for the edge node of OBS networks was proposed in this paper. By means of introducing the cross counter, the strategy presented in this paper adopt a dynamic threshold system, which was different from former assembly strategies that could be considered as a fixed threshold system. The novel strategy estimated the network traffic flow and chose a suitable assembly threshold dynamically by the cross counter, moreover, the value of assembly threshold modified by the step length according to the differences and similarities type of assembly threshold with former one. Simulation results demonstrate that the novel strategy can reduce the burst loss probability by 69.07% and 38.89% compared with the existing assembly strategies. Therefore, the novel strategy not only can adjust the assembly threshold according to the traffic flow, but also can achieve lower burst loss probability under strong self-similar case that be showed adapt to burst traffic.3. Proposed an analytical model for supporting multi-class service with the blocking probability analysis and adaptive routing strategy to solve the potential shortcomings in the real network. Making the use of the idea of segmented routes to separate routes according to the finite wavelength conversion resources. We then combine the each segment to obtain the whole blocking probability. The simulation results demonstrate that, by adopting the adaptive routing algorithms, the whole network can calculate the blocking probability for the candidate routes, and the request which takes the highest priority will choose the route with minimum blocking probability. There are two features in our paper. First, segmented route is designed. Second, use k-shortest routing algorithm to obtain the minimum blocking probability routing between source node and destination node.4. The protection scheme is a key topic in survivable wavelength division multiplexing (WDM) optical networks. In this paper, we investigate the issue of multicast requests in survivable networks against any single-link failure and present a novel scheme called segment protection with segment route (SPSR). Through dynamically adjusting link-cost according to the current network state, SPSR establishes a primary light-tree and corresponding link-disjoint backup segments for each multicast connection request. An analytical model was present for blocking probability analysis and adaptive routing algorithm to solve the potential shortcomings in the real network. We are making the use of the idea of segmented routes according to the branch nodes. Simulation results demonstrate that with the consideration of load balancing SPSR gets better blocking probability and resource utilization performance relative to other schemes.5. According to compare and analyze the advantages and shortcomings of three typical OBS simulation platforms, an OBS network simulation platform called OBS-NP (OBS-NS2-Platform) based on NS-2 was proposed. It extended the link class, node class, routing modular, schedule modular, assembly modular, control modular and traffic modular on the basis of NS-2, and provided the simulation surroundings for key Optical Burst Switching algorithms. After detailed descriptions for the structure of the OBS-NP system, a 16 nodes OBS network was taken as an example to obtain routing results and some significant network parameters such as the delay of the burst packets, throughput and resource utilization. Moreover,traffic result,schedule table,next hope routing information and Trace table are proposed. Finally, the accuracy and efficiency of the simulation results was discussed and analyzed.6. The architecture and corresponding control algorithm for a devised optical cross connect (Limited-range Wavelength Conversion, L-WIXC) are presented. The performance of L-WIXC including blocking probability, switching time, and throughput is simulated, while the cost comparison with wavelength selective cross connect and wavelength interchangeable cross connect is calculated. Key optical parameters, such as crosstalk, linear Q, bit error rate (BER) and eye diagram are also discussed and measured.