Which WAN technology was designed to give homes and small business high speed digital dial-up service over already existing communication infrastructure?（）

单项选择题You are preparing to create a point to point WAN by connecting a Cisco router with a Juniper router by way of their serial links. Which one of the following commands would you use?（）

A. TK1(config-if)# encapsulation hdlc ansi
B. TK1(config-if)# encapsulation ppp
C. TK1(config-if)# encapsulation LAPD
D. TK1(config-if)# encapsulation frame-relay ietf
E. TK1(config)#encapsulation ppp

单项选择题Which one of the WAN data-link protocols below is used for out-of-band signaling?（）

A. HDLC
B. NCP
C. PAP
D. LAPD
E. LAPB
F. None of the above

多项选择题Which of the following correctly describe characteristics of PPP?（）

A. Encapsulates several different types of routing protocols.
B. Supports only IP.
C. Can be used over analog circuits.
D. Is proprietary to Cisco
E. Supports error correction.

多项选择题What are some common layer 2 encapsulations for a WAN link?（）

A. Ethernet
B. PPP
C. Token Ring
D. HDLC
E. Frame Relay
F. POTS

单项选择题Which WAN service utilizes two different encapsulation types (one for data and one for signaling) on its data link layer?（）

A. ISDN
B. Frame Relay
C. ATM
D. FDDI