Research On Next Generation ROADM Node Structure And Associated Optical Network Performance

In recent years, new telecom business such as cloud computing, IPTV,020 (online tooffline) and IoT (Internet of Things) have been produced and experienced a rapid development, which is the significant trendency of telecommunications industry. Network operators start to build IP/MPLS over WDM to provision dynamic larger-bandwidth networks because of the overwhelming amount of information and telecommunications technology development. The next generation networks are more dynamic and unpredictable than traditional networks which need the WDM network served as physical layer to be more flexible and intelligent, to re-dispatch network resources flexibly and rapidly if topology or traffic demands changes.To provision network resources dynamically and flexibly, simplifynetwork planning, improve network resource utilization, ROADMs should be installed as switch node in backbone bearer network, which can change wavelength channels switching status under software control. WDM networks can be reconfigurable and develop toward intelligent networks by using ROADMs. The next generation ROADM generally demands three key features:colorless, directionless and contentionless (CDC). A set of contention mitigation hardware should be arranged in ROADM to realize the contentionless feature to avoid intra-node wavelength contention. However, extra hardware brings about higher TP-bank hardware cost and higher power consumption. Consequently, in the intra-node contention-aware ROADM optical network, the impact of different transponder (TP) resources on network performance is studied, in order to reduce redundanthardware. Thus, the optimized ROADM node can obtain contentionless feature, as well as make the optical network acquire the best network performance in practical.In this thesis, we design the ROADM structure with e-grooming capacity, build up an ILP model to dispatch network resources and introduce an intra-node contention-free heuristic algorithm. The impact of different TP resources on network performance is analyzed to optimize the ROADM structure and lower the cost and power consumption on the premise of best network performance. The causes of traffic blocking are analyzed finally. The active/standby structure and shared-by-node structure are used to study the impact of TP resources.Simulation results show that the ROADM node equipped with 2 TP banksis able to provide the contentionless feature. Furthermore, the number of TPs in the standby bank can be reduced to 37.5% of that in the active bank in the active/standby structure. The total number of TPs can be reduced to 68.7% with respect to the wavelength numbers in the shared-by-node structure. The simulations prove that the proposed ROADM structure cannot only decrease implemention cost and power consumption, but also maintain the network performance as well as "contentionless" structure.