Research On The Survivability And Elastic Mechanism In Long-Reach PON

With the explosive growth of Internet traffic and the increasing rate of optical network transmission,once the network fails,it will lead to serious data loss and service interruption.In order to make the data transmission avoid the faulty link as soon as possible,and improve the optical network survivability,a perfect fault monitoring location and protection switching mechanism is very important.In this paper,an efficient full protection mechanism of LR-PON is proposed for the current demand of optical network.After monitoring the fault location by monitoring the information,the NMS will control the protection mechanism by switching the optical switch.The protection scheme proposed in this paper can protect almost all optical fiber faults on the LR-PON:single fiber failure on the ring,multiple fiber faults in different segments of the fiber ring,double fiber failure in the same segment of the fiber ring,fiber link failures from RN to PSC,and fiber link failures from PSC to ONU.Through the theoretical analysis and simulation results,it can be seen that the proposed protection mechanism has low cost and low loss characteristics,while the network has high reliability of up to 99.9992%.In addition,the bit error rate both in the normal mode and the protection mode can meet the system requirements.In order to make the LR-PON survivability mechanism more stable and reliable,the system should be able to monitor all fiber links and devices in the entire network in real time,and the fault location should be determined as quickly and accurately as possible.To this end,we propose a high reliability fault detection and positioning mechanism,through the optical coding scheme to monitor all the network fiber links and network node status,and through the OTDR device and tunable switch to accurately locate the specific location of the fault.While fault detection is located,the system can protect against LR-PON from various faults.We analyzes the performance of recovery time,loss,cost,bit error rate and so on,the results show that the LR-PON fault detection and positioning scheme has the best results of cost and loss.In order to upgrade the existing limited coverage and non-elastic network PON system,this paper proposes a new SD-LR-PON system for long-distance metro access network,and designed a full-band multi-mode interference wavelength division multiplexer.Based on the pairwise interference and edge incident imaging mechanism,the mathematical model of the excitation region is established,and we completed the design of the full band demultiplexer based on the lithium niobate thin film and the silicon dioxide waveguide respectively.In addition,aiming at the characteristics of spectrum resource distribution in elastic optical network,a three-dimensional resource evaluation model based on time domain,wavelength domain and subcarrier domain is established,and we also established the spectral utility function based on the analysis of elasticity and spectral fragmentation.Using this function,the paper proposes an improved dynamic bandwidth allocation algorithm,which effectively reduces the resource debris of the network and improves the transmission efficiency.