Study On The Medium Access Control Protocol In Light-trail Network

With the rapid development of emerging internet services such as mobile internet and cloud computing, the performance of metro fiber optical network has caused more and more attention. Light-trail network had been considered as one of the promising solutions to improve the throughput of metro fiber optical network due to its efficient and flexible networking abilities. In this thesis, the medium access control(MAC) protocol in light-trail network was thoroughly studied as well as the mesh light-trail node architecture. Main works of this thesis were summarized as follows: Firstly, novel mesh light-trail node architecture was developed, which supported both global wavelength switching and local access wavelength switching with lower costs. And, a DWDM based optical communication platform was built to simulate the performance of light-trail network, whose node number ranged from three to six. The simulation result showed that the light-trail which adopted this mesh node architecture can travel up to five nodes. In this case, the BER of the optical service channel(OSC) channel was 1.73e-015 and Q factor was 7.86. The BER of the local access wavelength channel was 1.84e-016 and Q factor was 8.14. The BER of global wavelength channel was 3.53e-015 and Q factor was 7.78. Hence, the developed light-trail node architecture can meet the requirement of physical layer at mesh WDM networks for most cases.Secondly, to improve the performance of classical adaptive round time(ART) MAC protocol which lack of actual token holding evaluation, delay-aware adaptive round time(DAART) MAC was developed. DAART MAC which adopted the delay-aware mechanism can evaluate the actual token holding time of light-trail node. And then, the performance of light-tail networks which adopted ART MAC and DAART MAC respectively were simulated under three different traffic models. The simulation results showed that compared with ART, DAART can improve the throughput of light-trail network significantly.Thirdly, to furtherly improve the throughput of light-trail network, delay-aware adaptive round time for split light-trail(DAARTS) MAC protocol which combined both DAART MAC and light-trail split strategies was developed. The method to split light-trail according to different traffic models was devised, and then the performance of light-trail networks which adopted ART, DAART and DAARTS were simulated. Simulation result showed that compared with DAART, DAARTS can obtain 40.83% and 106.64% throughput improvement respectively for type one and type two traffic models.