单项选择题
Which benefit does digital subscriber line (DSL) systems for broadband access provide to the user?（）
A.Secure access to company extranet
B.Dedicated lines for high security data transfer
C.Simple solution for high-quality digital video using coaxial cable
D.Data and audio signals that share the same communications infrastructure
单项选择题 Which network technology allows for the monitoring of active communication networks to diagnose problems and gather statistics for network administration?（）
多项选择题 You are the network consultant from passguide.com. Do you know what attacks are software based attacks that disable your computer and attack user by e-mail?（）
单项选择题 How does a switch respond when it receives a message?（）