SDH（Synchronous Digital Hierarchy，同步数字体系）是一种将复接、线路传输及交换功能融为一体、并由统一网管系统操作的综合信息传送网络，是美国贝尔通信技术研究所提出来的同步光网络（SONET）。国际电话电报咨询委员会（CCITT）（现ITU-T）于1988年接受了SONET 概念并重新命名为SDH，使其成为不仅适用于光纤也适用于微波和卫星传输的通用技术体制。 它可实现网络有效管理、实时业务监控、动态网络维护、不同厂商设备间的互通等多项功能，能大大提高网络资源利用率、
The Multi-Protocol Label Switching - Transport Profile (MPLS-TP) is the result of a joint effort by the Internet Engineering Task Force (IETF) and the International Telecommunication Union (ITU-T) based on their previously respective and separate wo
mpls-tp oam A maintenance entity (ME) can be viewed as the association between two MEG end points (MEPs) that applies maintenance and monitoring operations to a network connection or a tandem connection. In the case of a co-routed bidirectional poin
