| As network traffic is quickly increasing and dense wavelength division multiplexing (DWDM) technology is widely used,optical networks and optical switching become research focus. Optical switching can remove O/E/O conversion in electronic switching, improve the switching capacity, and break through the switching bottleneck of transmission network. Combining the merits of optical packet switching and optical circuit switching, and overcoming their defects, optical burst switching (OBS) is considered as a promising switching paradigm for next optical networks. The basic principle of OBS networks is discussed. The data channel scheduling algorithm, assembly algorithm and quality of service (QoS) mechanism of OBS networks are analyzed in the paper. A batch scheduling algorithm based on latest available unscheduled channel (LAUC), a proportional differentiation mechanism based on batch scheduling and a pipeline scheme supporting real-time traffic are proposed for OBS networks. Then based on these research results a new burst-enalbed optical switching, including burst enabled multi-granularity optical switching and hybrid optical switching that can support switching granularity of burst and wavelength, is researched in the paper. A hybrid optical switching with self-adaptation is proposed to efficiently utilize the merits of OBS and optical circuit switching and meet the requirement of traffic QoS. A multi-granularity optical cross connect (MG-OXC) contained optical add-drop multiplexer and a burst-enabled multi-granularity optical switching paradigm including node architecture, route policy and waveband assignment are proposed to reduce the cost of optical switching node. The innovative work in the paper is summarized as follows.(1) A batch scheduling algorithm based on LAUC (BS-LAUC) is proposed in the paper. Data channel scheduling algorithm is the key algorithm in OBS networks. LAUC algorithm has low complexity of computation and its burst dropping probability is high. Latest available unused channel with Void Filling (LAUC-VF) algorithm has low burst dropping probability and its computation complexity is high. An algorithm that has low computation complexity and burst dropping probability is required for OBS networks. Aiming at this instance, a batching scheduling algorithm based on LAUC and the scheduling order of burst arrival time is proposed in the paper. At first, BS-LAUC buffers many burst control packets (BCP). When the max buffer time arrives, the BCPs in the buffers are batching scheduled and processed with burst arrival order. And LAUC algorithm is used to reserve data channel resource for data bursts. Based on LAUC, BS-LAUC only adds buffering and changes the scheduling order. So BS-LAUC is as simple as LAUC. Simulation results show that BS-LAUC not only outperforms LAUC in terms of burst dropping probability, but also outperforms LAUC-VF when the max buffer time is equal to the deduced optimum value that is the maximum difference of the offset time.(2) A proportional differentiation scheme based on batch scheduling (PDS-BS) is proposed in the paper. How to provide different QoS for the different priority traffic is a research focus in OBS networks. Proportional differentiation scheme is very convenient for network operators to control the relative quality differentiation among service classes by adjusting the proportional differentiation parameters. The proposed scheme adopts the batch scheduling idea to decrease burst dropping probability. And it adopts a preemption method to keep a proportional burst dropping probability among service classes according to the expected burst dropping probability of different traffic given by the proportional differentiation model. Compared with other Proportional differentiation scheme, PDS-BS has the following merits. Based on LAUC, PDS-BS only adds batch scheduling and preemption. And the preemption is confined in the last data burst of each data channel. So the computation complexity of PDS-BS is low. Simulation results show that PDS-BS can provide proportional differentiated services and efficiently decrease burst dropping probability.(3) Based on the delay analysis of OBS networks, a pipeline scheme is proposed to reduce the delay of real-time traffic in the paper. When the data burst of real-time traffic pass through the established pipeline, its burst control packets are not need to be processed since the data channel in pipeline has already reserved. Thus the pipeline scheme can reduce the offset time and network delay of real-time traffic. When the pipeline is idle, it can be used by non-real-time traffic to improve the pipeline utilization. Simulation results show that the pipeline scheme can effectively reduce the end to end delay of the real-time traffic.(4) A hybrid optical switching with self-adaptation(S-HOS) is proposed in the paper. Hybrid optical switching combines the merits of OBS and optical circuit switching, and can support the switching granularity of burst and wavelength. However currently hybrid optical switching only simply overlays optical circuit switching and OBS. Its complexity is high and link utilization is low. S-HOS is proposed to solve the problem. According to the dynamic variation of network traffic, S-HOS can adjust optical switching paradigm. Based on minimum burst length maximum assembly period algorithm, a new assembly algorithm of S-HOS is proposed to improve the lightpath utilization and efficiently support bursty traffic. And S-HOS can use data channel scheduling algorithms to assign data channel resource for the lightpaths and data bursts by regarding lightpaths as a huge virtual data bursts. This helps to reduce the complexity of hybrid optical switching. Simulation results show that S-HOS can reduce IP packet dropping probability and end-to-end delay.(5) A multi-granularity optical cross connect (MG-OXC) contained optical add-drop multiplexer (OADM) is designed in the paper. Optical cross connect (OXC) is key architecture of optical switching. Many wavebands and wavelength that do not need to be switched are connected to OXC in the current MG-OXC. This wastes many ports of MG-OXC. A MG-OXC contained OADM is designed to reduce the port numbers of MG-OXC and node costs by OADM that connect OXCs with the wavebands and wavelengths required to be switched.(6) A burst-enabled multi-granularity optical switching (MOS) is proposed in the paper. In general, current MOS can support three granularities, i.e., fiber, waveband and wavelength. And its smallest switching granularity is wavelength. These switching granularities are too big for a lot of bursty network traffic. Thus the link utilization is low. A burst-enabled MOS that combined with OBS is proposed to improve the network performance in the paper. A burst-enabled MOS can use the statistical multiplexing characteristic of OBS to improve the performance of link utilization. And it use MOS to reduce the port number and costs of OXC. The policy of waveband assignment, node architecture and route policy of burst-enabled MOS are proposed in the paper. Simulation results show that burst-enabled MOS can reduce the packet dropping probability and end-to-end delay.
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