单项选择题
A. Ensuring secure presentations
B.Augmenting an existing network
C.Providing a temporary network need
D.Having freedom of movement within a network range
单项选择题 Which IP telephony component provides call processing, such as signaling, that in a traditional voice network is provided by switching equipment, such as a PBX?（）
单项选择题 Which software-based security threat is typically spread from user to user via e-mail?（）
单项选择题 Which Cisco product is a hardware component that supports content filtering and other gateway security functions for the Catalyst 6500 Series?（）