Which two Internet Protocol (IP) telephony devices are best categorized as infrastructure components? （）

单项选择题What ensures that voice packets are given priority throughout the network so that conversations arrive intact?（）

A.QoS
B.Centrex
C.Packet encryption
D.Intelligent call routing

单项选择题Why is QoS important in a converged network?（）

A.Because data does not need to arrive intact, so data transfer rates can be variable
B.Because lost voice-data packets must be retransmitted
C.Because voice data packets should arrive quickly and sequentially, and with no lost data
D.Because voice data packets must follow a single dedicated path through the network

单项选择题You are the network consultant from passguide.com. Could you please tell customers what strategy will protect network resources and services from unauthorized actions?（）

A.Network management
B.Network optimization
C.Network security
D.Content storage networking

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?（）

A.Stores data on the network and connects the local-area network (LAN) to the wide-area network (WAN)
B.Routes traffic down alternative paths and connects the local-area network (LAN) to the wide- area network (WAN)
C.Broadcasts data to all devices that are connected to it across the local-area network (LAN) and wide-area network (WAN)
D.Reads Media Access Control (MAC) addresses to forward messages to the correct location and connects the local-area network (LAN) to the wide-area network (WAN)