EPON系统中ONU端口环路检测方案及实现

摘要

在以太网无源光网络( EPON)系统中,光网络单元(ONU)用户端口成环将会造成同一个无源光网络口下所有的业务中断.首先分析了EPON系统中ONU侧用户端口可能造成环路的主要原因及危害;然后提出了分别在OLT侧和ONU侧构造特殊报文进行环路检测的方案,并简要比较了它们的优缺点;最后对OLT侧环路检测方案的设计实现进行了重点描述.实践证明,采用OLT侧特殊报文检测方案能够有效地发现和防止ONU侧用户端口环路.%In EPON systems, ONU user ports' loopbacks will cause the discontinuation of all the services at the same PON port. This paper first analyzes the common causes for the loopbacks and the serious consequences arising from them. Then it proposes the schemes about the port loopback detection both in OLT side and ONU side and presents the advantages and disadvantages between them. Finally the port loopback detection scheme about using "special package detection" method in OLT side is described briefly. In conclusion the "special package detection"scheme can discover and prevent the ONU user port loopback effectively.