Network + Guide to Networks Chp 7

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88 terms · Network + Guide to Networks Chp 7


T/F: In a star topology, a single connection failure will halt all traffic between all sites.


T/F: Dial-up ISDN does not convert a computer's digital signals to analog before transmitting them over the PSTN.


T/F: ATM is a WAN technology that functions in the Data Link layer.


T/F: SONET specifies framing and multiplexing techniques at the Physical layer.


T/F: The PPTP VPN tunneling protocol is based on technology developed by Cisco.


WANs typically send data over ____ available communications networks.

WAN sites

The individual geographic locations connected by a WAN are known as ____.


Because WAN connections require routers or other Layer 3 devices to connect locations, their links are not capable of carrying ____ protocols.


On most modern WANs, a ring topology relies on ____ rings to carry data.

local loop

The portion of the PSTN that connects any residence or business to the nearest CO is known as the ____.


A PSTN offers ____ security.

frame relay



In a process called ____, two 64-Kbps ISDN B channels can be combined to achieve an effective throughput of 128 Kbps.

terminal adapter

A ____ converts digital signals into analog signals for use with ISDN phones and other analog devices.


ISDN PRI uses ____ B channels and one 64-Kbps D channel.


The speed of a T-carrier depends on its ____ level.

smart jack



A ____ aggregates multiple DSL subscriber lines and connects them to the carrier's CO.



fixed packet

What sets ATM apart from Ethernet is its ____ size.

fault tolerance

SONET's extraordinary ____ results from its use of a double-ring topology over fiber-optic cable.

OC level





____ is the preferred communications protocol for remote access communications.





virtual circuits



A(n) ____________________ uses TDM (time division multiplexing) over two wire to divide a single channel into multiple channels.


____ encapsulates incoming Ethernet or token ring frames, then converts them into ATM cells for transmission over an ATM network.

remote desktop

____________________ is the remote virtual computing software that comes with Windows client and server operating systems.



signal level

Refers to the T-carrier's Physical layer electrical signaling characteristics as defined by ANSI standards in the early 1980s.


Occurs when data travels from the customer to the carrier's switching facility.


Occurs when data travels from the carrier's switching facility to the customer.

bus topology WAN

Occurs when each site is directly connected to no more than two other sites in a serial fashion.

symmetrical technology

Provides equal capacity for data traveling both upstream and downstream.

asymmetrical technology

Occurs when downstream throughput is higher than upstream throughput.

star topology WAN

Contains a single site acting as the central connection point for several other points.

mesh topology WAN

Incorporates many directly interconnected sites.

tiered topology WAN

Contain sites that are connected in star or ring formations are interconnected at different levels, with the interconnection points being organized into layers to form hierarchical groupings.

Local Loop


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?

To carry call session information

What is the purpose of ISDN'S D channel?


Suppose you work for a bank and are leasing a frame by 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 permission?

D. Terminal adapter

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


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?

B. 2

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 the network should you install the router?

B. between the cable modem and the workstation


D. It uses fixed- sized cells to carry data

You work for and 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?

A. OC1

Which two of the following are asymmetrical versions of DSL?





C. Time division multiplexing

Where on the PSTN would you most likely find a DSLAM?

A. In a remote switching facility


C. Ten T1s

You're troubleshooting a problem with a T1 connection between your business and the service provider's facility. The t1 connection intermittently goes down. When you call the service provider for assistance, they say they will only engage one of their technicians after you have verified that all of your premises equipment is in working order. Given the requirements, which of the following do you not examine for faults?

D. The cable that enters your smart jack from outside your building

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?

C. 2Mbps


A. Its double-ring topology

Which of the following may limit a DSL connection's capability?

D. The distance from the customer to the carrier's switching facility

You have just started working for a regional network service provider. The company provides several T1s to businesses around your city. In addition, your company supplies Internet service to three ISPs, using multiple T1s. Two T3s connect your employer's data center with two even larger service providers. You notice a router in the data center that handles the multiple T1s and T3s. Which of the following routing protocols is this router almost certainly running to exchange rout information with routers on the other service provider's network?



A variation of DSL that offers more throughput when data travel downstream, downloading from a local carriers switching facility to the customer.


The characteristics of a transmission technology that affords greater bandwidth in one direction than in the other direction.


A transmission method in which data being transmitted and received by nodes do not have to conform to any timing scheme.


Asynchronous Transfer Mode

ATM (Asynchronous Transfer Mode)

A data link layer technology originally conceived in the early 1980s at Bell Labs and standardized in the 1990s.

B Channel

In ISDN, the bearer channel, so named because it bears traffic from point to point.


Basic Rate Interface


The process of combining more than one bearer channel of an ISDN to increase throughput.


Broadband over powerline

BPL (Broadband over powerline)

High speed internet access delivered over the electrical grid.

BRI (Basic Rate Interface)

A variety of ISDN that uses two 64-kbps bearer channel and on 16-kbps data channel.

Broadband Cable

A method of connecting to the internet over a cable network.

Bus Topology WAN

A WAN in which each location is connected to no more than two other locations in a serial fashion.

Cable drop

The fiber-optic or coaxial cable that connects a neighborhood cable node to a customers house.

Cable modem

A device that modulates and demodulates signals for transmission and reception via cable wiring.


A cell consists of 48 bytes of data plus a 5 byte header.


Committed Information Rate

CIR (committed information rate)

The guaranteed minimum amount of bandwidth selected when leasing a frame relay circuit.


Central Office

CO (Central Office)

The location where a local or long - distance telephone service provider terminates and interconnects customer lines.


Channel Service Unit

CSU (channel service unit)

A device used with T-carrier technology that provides termination for the digital signal and ensures connection integrity through error connection and line monitoring.


A combination of CSU and a DSU that serves as a connection point for a T1 line at the customers site.

D Channel

The "data" channel is used to carry information about the call such as session initiation and termination signals, caller ID, call forwarding, and conference call signals.


A continuously available link or service that is leased through another carrier.


A type of connection in which a user connects to a distant network from a computer and stays connected for a finite period of time.


A term used to describe data traffic that flows from a carrier's facility to the customer.

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