单项选择题
Which network technology addresses these customer business needs: shrinking budgets and IT staffs, more complex networks, and an increased need for network security?（）
A.Optical network B.Network management C.Storage-area network (SAN) D.Content delivery network (CDN)
单项选择题 What does a router do?（）
单项选择题 Which component should you use to reduce collision issues on a large LAN?（）
单项选择题 In the 7-layer OSI model, which layer switching will take place?（）
