Which of the following WAN topologies comes with the highest availability and the greatest cost?
Which of the following elements of the PSTN is most likely capable of transmitting only analog signals?
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?
What is the purpose of ISDN's D channel?
To carry call session information
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 will experience?
On an ISDN connection, what device separates the voice signal from the data signals at the customer premises?
Which WAN technology operates at Layer 3 of the OSI model?
None of the above
What technique enables DSL to achieve high throughput over PSTN lines?
Suppose you establish a home network and you want all three of your computers to share one broadband cable connection to the Internet. You decide to buy a router to make this sharing possible. Where on your network should you install the router?
Between the cable modem and the workstations
How does ATM differ from every other WAN technology described in this chapter?
It uses fixed-sized cells to carry data
You work for an Internet service provider that wants to lease a T3 over a SONET ring. What is the minimum Optical Carrier level that the SONET ring must have to support the bandwidth of a T3?
Name two asymmetrical versions of DSL
ADSL and VDSL
What technique does T1 technology use to transmit multiple signals over a single telephone line?
Time Division Multiplexing
Where on the PSTN would you most likely find a DSLAM?
In a remote switching facility
The science museum where you work determines that it needs an Internet connection capable of transmitting and receiving data at 12 Mbps at any time. Which of the following T-carrier solutions would you advise?
A local bookstore that belongs to a nationwide chain needs a continuously available Internet connection so that staff can search for the availability of customer requests in the database stored at the bookstore's headquarters. The maximum throughput the store needs is 768 Kbps. Which of the following options would best suit the store?
What part of a SONET network allows it to be self-healing?
Its double-ring topology
Which of the following may limit a DSL connection's capacity?
The distance from the customer to the carrier's switching facility
You work for a consulting company that wants to allow telecommuting employees to connect with the company's billing system, which has been in place for 10 years. What do you suggest as the most secure and practical means of providing remote LAN access for this application?
Dialing into a terminal server that is connected to the same network as the billing system server
Why is broadband cable less commonly used by businesses than DSL or T-carrier services?
Because most office buildings are not wired with coaxial cable
You're troubleshooting a problem with poor performance over a WAN connection at your office. Looking at the smart jack, you see the Tx light is blinking green and the Rx light is not illuminated. What can you conclude about the problem?
It is likely due to faults in your service provider's network.
Your company has decided to order ADSL from its local telecommunications carrier. You call the carrier and find out that your office is located 17,000 feet from the nearest CO. Given ADSL's potential throughput and your distance from the CO, what is the maximum downstream throughput you can realistically expect to achieve through this connection?
In which of the following situations would you use RDP?
To establish a VPN between your home workstation and your office LAN
You have decided to set up a VPN between your home and your friend's home so that you can run a private digital telephone line over your DSL connections. Each of you has purchased a small Cisco router for terminating the VPN endpoints. Which of the following protocols could you use to create a tunnel between these two routers?
A VPN is designed to connect 15 film animators and programmers from around the state of California. At the core of the VPN is a router connected to a high- performance server used for storing the animation files. The server and router are housed in an ISP's data center. The ISP provides two different T3 connections to the Internet backbone. What type of connection must each of the animators and programmers have to access the VPN?
Any type of Internet connection