SDH的概念最早由美国贝尔通信研究所提出，称为SONET（同步光网络）。
SDH的概念最早由美国贝尔通信研究所提出，称为SONET（同步光网络）。
相关考题：
关于MSTP的说法，哪个是错误的：（）A、华为最早提出RPR的概念B、2000年北展华为首次推出MSTP的概念C、华为最早出现ATM OVER SDH规模商用D、华为最早推出IP OVER SDH
On an ONS 15454 node you can tunnel a（n） （）.A、 SDH circuit over a SONET network delivering it as an SDH signalB、 SDH circuit over a SONET network delivering it as a SONET signalC、 SONET circuit over an SDH network delivering it as an SDH signalD、 SONET circuit over an SDH network delivering it as a SONET signal
POS（PacketOverSONET/SDH，SONET/SDH上的分组）将长度固定的数据包直接映射进SONET同步载荷中，使用SONET物理层传输标准，提供了一种高速、可靠、点到点的数据连接。
On an ONS 15454 node you can tunnel an （）.A、SDH circuit over a SONET network delivering it as an SDH signalB、SDH circuit over a SONET network delivering it as a SONET signalC、SONET circuit over an SDH network delivering it as an SDH signalD、SONET circuit over an SDH network delivering it as a SONET signal
单选题On an ONS 15454 node you can tunnel a（n） （）.A SDH circuit over a SONET network delivering it as an SDH signalB SDH circuit over a SONET network delivering it as a SONET signalC SONET circuit over an SDH network delivering it as an SDH signalD SONET circuit over an SDH network delivering it as a SONET signal
单选题On an ONS 15454 node you can tunnel an （）.ASDH circuit over a SONET network delivering it as an SDH signalBSDH circuit over a SONET network delivering it as a SONET signalCSONET circuit over an SDH network delivering it as an SDH signalDSONET circuit over an SDH network delivering it as a SONET signal