单选题 （ ）大大延长了无电中继距离Which of the following devices substantially extend the electroless trunk distance? ( )

单选题 早期的WDM，是对1310nm和1550nm的光进行两路复用，现在的DWDM，则是对（ ）的光进行密集多路复用The WDM in the early stage performs two-wavelength multiplexing on 1310nm and 1550nm light. The DWDM now performs the dense multi-wavelength multiplexing on the light ( )

单选题 OTN标准中，只用于封装GE的业务的ODU类型为：（ ） In OTN standard, which of the following ODU types is only used to encapsulate GE service?

单选题 OTN新补充的标准对GE的映射提出了明确的封装要求；（）是OTN专门针对GE业务封装调度的颗粒，其引入体现了OTN标准的精髓。 Explicit encapsulation requirements for GE mapping are defined in new OTN standard; ( ) is the granularity for OTN to encapsulate GE service, which is the essence of OTN standard.

单选题 OTU2的帧bit rate是多少？（ ） Which of the following is the frame bit rate of OTU2?

单选题 OTU1的帧bit rate是多少？（ ） Which of the following is the frame bit rate of OTU1?

单选题 TCM用于检测ODUk的各种连接情况,在ODUk帧中，TCM开销共有( )组。 TCM is used to detect various connections of ODUk; in ODUk frame, in total there are ( ) groups of TCM overheads.

单选题 在OTN的帧结构中,OTU1帧的帧周期是（）。 In OTN frame structure, frame period of OTU1 frame is ( ).

单选题 DWDM的意思是DWDM is short for ( ).