The Link Protection Switchover Of PON System

Through the development of the last few years,the PON technology has beenbecoming mature and been widely used. It is necessary to realize the technology of PONprotection switching in order to guarantee the operational stability of system in engineeringapplication and take countermeasures against correspondence malfunction. The function ofPON protection switching is to trigger protection switching,and the completion of theswitchover to resume operations when the main PON port detectes PON port optical signalabnormalities or single board offline alarms.This paper researches the protection switching that is aimed at G\EPON system. Thecore idea of protection switching is to use redundancy to improve system reliability. PONprotection switching redundancy protection can be divided into two categories: trunk fiberredundancy protection and optical path redundancy protection. Passive Optical Network(PON) systems commonly used-to-multipoint tree topology,its trunk fiber survivabilityissues is related to the reliability of the entire PON system， therefore it is very necessaryto protect the trunk fiber.This paper introduces the four types of optical link protection switching,A, B,C,D.From the system hardware structure,the paper analysis disk-inner,disk-among PONprotection program, as well as system software structure and introduce the realization ofPON protection switching with modules.In order to achieve quickly restored of businessand a smooth transition after switchover，before the switchover occurs， the standby statePON port must have the same configuration with the primary state protection group,eachPON port configuration information and ONU configuration information need to besynchronized. After the implementation of the the PON switchover,the original standbyPON port becomes the primary PON port and all of the PON port related configuration andONU configuration authorization information (such as ONU authorizationinformation,service configuration) should be the same as the original primary PON port.After the completion of PON port protection switching,and in the case of new master PON port is available,all business can be automatically recovered.This is a PON system optical line protection device which is low-cost and can beautomatically switched. Finally,experiments verify the PON system automatically andconstrainedly switching function and recovery time of switching,the trunk protectionswitching business interruption time within50ms,as well as the full protection switchingbusiness interruption time within50ms.