Hybrid Switching Optical Network Optimization Design

Although the emergence of Wavelength Division Multiplexing (WDM) opens up the Terahertz transmission bandwidth, the processing capability of the electronic parts of core routers lead to electronic bottlenecks, which restrict optical networks development. Three basic optical switching technologies in WDM networks are proposed. Optical Circuit Switching (OCS) has high transmission efficiency, Optical Packet Switching (OPS) and Optical Burst Switching (OBS) can effectively accommodate dynamical traffic. But OPS requires maturity in a number of component/system technologies which are still experimental in research laboratories. In recent years, some researchers turn to optimizing network performance by collaboratively combining the strengths of basic optical switching technologies and avoiding/reducing their weaknesses as much as possible. Consequently, three types of hybrid architectures are identified—Client-Server, Paraell and Integrated. However, these hybrid models also have problems such as, virtual topology design, network realization, efficient utilization of network resources, and etc. Based on these situations, this thesis proposes a novel hybrid network architecture, named Cycle-based Hybrid Switching Optical Networks (CHSON).The CHSON's design scheme is introduced in Chapter 2. CHSON can efficiently support bursty traffic patterns of current networks. It integrates highly efficient transportation of Optical Circuit Switching with statistical multiplexing of Optical Burst Switching. CHSON could not only reduce the strain on packet forwarding of traditional point to point WDM solutions to relieve electronic bottleneck, but also accommodate bursty traffic and achieve better bandwidth efficiency than all-optical wavelength switching networks (i.e., OCS networks). This chapter first introduces the overall architecture of CHSON as well as virtual topology design involved. Then CHSON's node design and implementation are illustrated. One typical feature of CHSON is its virtual topology design approaches. Specifically, the virtual topology of OBS part is a ring. Ring topology can sustain connectivity of networks while occupying rather few wavelength resources, and also have natural self-heal capability. Simulation results show that CHSON utilizes the high transmission efficiency of OCS technology without sacrificing the ability of accommodating bursty traffic. In addition, static configuration of network nodes and the two mature switching technologies involved make CHSON easily realize.The third chapter describes CHSON's optimal design schemes, including CHSON capacity design model, survival CHSON research, general virtual topology design approach and conflict resolution strategy. According to CHSON's charactieristcs, first ILP models for the overall CHSON capacity design are proposed. Then referring to the existent protection mechanisms, three different proctection models are promoted--path_based protection model, link_based protection model and P-cycles model, which aim at enhancing CHSON's survivability. In addition, OBS topology design methods mentioned in the second chapter are only suitful for the physical topology with Hamitlon cycles, this chapter will introduce a general sheme for establishing virtual topology of OBS part. Finally, contention resolution mechanisms of CHSON are discussed, which help to improve network reliability further.To verify and evaluate the switching technology in the previous chapter, an optical network simulation platform has been developed using OPNET tool. In Chapter 4, we will brief the framework of the platform, and the designation and data structures of different modules are given too.