1. Which of the following best describes the main function of OSI Layer 1 protocols?
a. Framing
b. Delivery of bits from one device to another
c. Addressing
d. Local Management Interface (LMI)
e. DLCI
Table 4-1 “Do I Know This Already?” Foundation Topics Section-to-Question Mapping
Foundation Topics Section Questions
OSI Layer 1 for Point-to-Point WANs 1–4
OSI Layer 2 for Point-to-Point WANs 5, 6
Frame Relay and Packet-Switching Services 7, 8
78 Chapter 4: Fundamentals of WANs
2. Which of the following typically connects to a four-wire line provided by a telco?
a. Router serial interface without internal CSU/DSU
b. CSU/DSU
c. Router serial interface with internal transceiver
d. Switch serial interface
3. Which of the following typically connects to a V.35 or RS-232 end of a cable when
cabling a leased line?
a. Router serial interface without internal CSU/DSU
b. CSU/DSU
c. Router serial interface with internal transceiver
d. Switch serial interface
4. On a point-to-point WAN link using a leased line between two routers located
hundreds of miles apart, what devices are considered to be the DTE devices?
a. Routers
b. CSU/DSU
c. The central office equipment
d. A chip on the processor of each router
e. None of these answers are correct.
5. Which of the following functions of OSI Layer 2 is specified by the protocol standard
for PPP, but is implemented with a Cisco proprietary header field for HDLC?
a. Framing
b. Arbitration
c. Addressing
d. Error detection
e. Identifying the type of protocol that is inside the frame
“Do I Know This Already?” Quiz 79
6. Imagine that Router1 has three point-to-point serial links, one link each to three remote
routers. Which of the following is true about the required HDLC addressing at
Router1?
a. Router1 must use HDLC addresses 1, 2, and 3.
b. Router1 must use any three unique addresses between 1 and 1023.
c. Router1 must use any three unique addresses between 16 and 1000.
d. Router1 must use three sequential unique addresses between 1 and 1023.
e. None of these answers are correct.
7. What is the name of the Frame Relay field used to identify Frame Relay virtual
circuits?
a. Data-link connection identifier
b. Data-link circuit identifier
c. Data-link connection indicator
d. Data-link circuit indicator
e. None of these answers are correct.
8. Which of the following is true about Frame Relay virtual circuits (VCs)?
a. Each VC requires a separate access link.
b. Multiple VCs can share the same access link.
c. All VCs sharing the same access link must connect to the same router on the
other side of the VC.
d. All VCs on the same access link must use the same DLCI.