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？（）
A. 225 ft B. 450 ft C. 655 ft D. 900 ft
单项选择题 WhyisanSTM-12F-MS-SPRingNOTfeasible？（）
单项选择题 You are provisioning an E-1 circuit on an ONS 15454 SNCP configuration and XC-VXL-10G card. How many total ports are used within the Low-Order matrix at the source node？（）
多项选择题 Whataretwocharacteristicsofdual-ringinterconnectinSDHnetworks？（）
