多项选择题
A. line timing
B. loop timing
C. internal timing
D. through timing
E. external timing
单项选择题 TheML-seriesEthernetcardontheONS15454providesupto（）activeQ-in-Qinstancespercard.
单项选择题 You are installing a Cisco ONS 15454 SDH in a service provider site. An E3 cable is being connected to a digital cross-connect system. What is the maximum distance allowed between the two？（）
单项选择题 WhyisanSTM-12F-MS-SPRingNOTfeasible？（）