Wide Area Networks

Which of the following elements of the PSTN is most likely capable of transmitting only analog signals?

• Central office

• Local loop

• CSU/DSU

• Remote switching facility

Which of the following WAN topologies comes with the highest availability and the greatest cost?

• Bus

• Tiered

• Partial mesh

• Full mesh

A customer calls your ISP’s technical support line, complaining that his connection to the Internet usually goes as fast as 128 Kbps, but today it is only reaching 64 Kbps. He adds that he has tried dialing up three different times with the same result. What type of connection does this customer have?

• PSTN dial-up

• DSL

• ISDN

• T1

What is the purpose of ISDN’s D channel?

• To carry call session information

• To carry error-checking information

• To enable time division multiplexing

• To carry data

Suppose you work for a bank and are leasing a frame relay connection to link an automatic teller machine located in a rural grocery store with your bank’s headquarters. Which of the following circuits would be the best option, given the type of use this automatic teller machine experience?

• DLC

• PVC

• SVC

• HLC

On an ISDN connection, what device separates the voice signal from the data signals at the customer premises?

• Network termination

• Terminal equipment

• Multiplexer

• Terminal adapter

Which of the following WAN technologies operates at Layer 3 of the OSI model?

• ATM

• DSL

• SONET

• None of the above

You work for a regional common carrier and have been asked to design a passive optical network that will bring high-speed Internet access to a new neighborhood in a nearby suburb. The area served by the network will bring fiber-optic cable to as many as 45 households. At least how many ports on the carrier’s OLT should you expect to configure?

• 1

• 2

• 3

• 4

You offer your networking expertise to a small nonprofit organization. The three employees each have a desktop computer and want to share the single broadband cable Internet connection that comes to their office. You donate a router you have sitting around to make this sharing possible. Where on your network should you install the router?

• Attached to one of the end workstations

• Between the cable modem and the cable drop

• Attached to a server that’s connected to the cable drop

• Between the cable modem and the workstations

How does ATM differ from every other WAN technology described in this chapter?

• It does not use packet switching.

• It requires fiber-optic media.

• It does not provide error detection or correction.

• It uses fixed-sized cells to carry data.