Hybrid Switching The Light On The Optical Network Multicast Mechanism

There are two all-opitcal multicast vshemes in WDM networks:one is light-tree based multicast in OCS(Optical Circuit Switching)networks,and anther is packet based multicast in OBS(Optical Burst Switching)networks. However, both of them have disadvantages.In the OCS network, the multicast sessions are transported by the light-trees and a light-tree can provide as much as gigabit bandwidth, but a muticast session only need a small part of it.So the utilization of the bandwidth in the OCS network is very low。Although the Multicast Traffic Grooming in Wavelength-Routed network can improve the utilization of the bandwidth, it has high cost and a complexity algorithm.The multicast on the OBS network has also been studied. In the OBS network, it has a good utilization of the bandwidth but can't meet the need of low packet loss probability and packet latancy.In this paper, we first analyse the disadvantages of the OCS and OBS multicast vshemes and then we propose a Hybrid optical switching network called c-Hylabs(Cycle based Hybrid Lightpath And Burst Switching) and propose an efficient multicast vsheme on c-Hylabs. Simulation demonstrate that the c-Hylabs multicast vsheme performs better than OBS multicast vsheme in terms of packet loss probability and packet latancy.All Three basic optical switching technologies in WDM networks have their defaults, so 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 novel hybrid network architecture, named Cycle-based Hybrid Switching Optical Networks(c-HyLabs). C-HyLabs 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. c-HyLabs 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 c-HyLabs。Then c-HyLabs's node design and implementation will be illustrated in the next chapter when we talked about the c-HyLabs multicast vsheme. One typical feature of c-HyLabs 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.In the second chapter, we introduce a multicast vsheme on the c-HyLabs network which is called circle-based HyLabs multicast vsheme.In the first; we introduce the basic muticast vsheme and its implementation on the circle-based HyLabs network.Then we introduce virtual topology design; the node design and implementation are also illustrated。Simulation results show that circle-based HyLabs multicast vsheme utilizes the high transmission efficiency of OCS technology without sacrificing the ability of accommodating bursty traffic, and circle-based Hylabs multicast vsheme performs better than OBS multicast vsheme in terms of packet loss probability and packet latancy.In the last part, we present a heuristive method to find a vs node which can improve the perfornabce of network.In the third chapter, we introduce another multicast vsheme called tree-based HyLabs multicast vsheme.In the first; we introduce the basic muticast vsheme and its implementation, the virtual topology design is also involved. Simulation results show that tree-based HyLabs multicast vsheme utilizes the high transmission efficiency of OCS technology without sacrificing the ability of accommodating bursty traffic, and tree-based c-Hylabs multicast vsheme performs better than OBS multicast vsheme in terms of packet loss probability and packet latancy。In the last part, we present a heuristive method to find a vs node which can improve the perfornabce of network.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.