多项选择题
A.Encryption
B.Minimal signal loss
C.Bandwidth limits
D.No EMI
多项选择题 Which three are Cisco architectures?（）
多项选择题 What are five of the seven layers that are found in the OSI model?（）
单项选择题 Cisco Technical Support Services portfolio provide customers resources that help ensure that Cisco products operate efficiently, remain highly available, and benefit from up-to-date system software. Is it correct?（）