EPON系统中ONU软件远程升级方案的设计

Design of Remote Upgrades for ONUs Software in EPON System

随着EPON（以太无源光网络）设备的广泛使用，对这些大数量、分布式的ONU（光网络单元）设备进行快速便捷的软件升级是EPON系统重要功能之一。文章提出了一种新的ONU软件远程升级方案，该方案的主要思路是：由网管系统下发升级命令，通过TFTP协议和OAM协议传送升级文件并进行下载和烧写等工作。为了使程序在升级失败后仍能正常运行，采用双镜像升级方法来完成镜像的烧写。实验测试证明该方案的正确性以及双镜像升级方法的有效性，有效解决了ONU软件升级时发生意外情况而导致系统无法正常工作的问题。

With the widespread use of EPON equipment, upgrading the software for the ONU equipments which are in large quantities and scattered is one of the important function of EPON system. Therefore, a new whole process of remote upgrading of ONUs is proposed in this paper. The main idea is that the upgrading command is issued by the network management system and the the upgrading files are transferred, downloaded and burnt through TFTP protocol and OAM protocol . In order to run normally after the failure of upgrading files for the system , double image is adopted to burn Flash ROM. Experiment test proves the correctness of the proposed system and the effectiveness of the double image. Moreover, it solves the problem that the unexpected situations break down the system when the upgrade of ONU software is going.