Deck 7: Wide Area Networks

Question 1

In a star topology, a single connection failure will halt all traffic between all sites.

Answer 1

False

Question 2

____ WANs are the most fault-tolerant type of WAN because they provide multiple routes for data to follow between any two points.

A) Bus
B) Star
C) Mesh
D) Tiered

Answer 2

C

Question 3

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

A) open
B) standard
C) routable
D) nonroutable

Answer 3

D

Question 4

After SONET, BPL has the best maximum throughput available.

Question 5

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

A) flexible
B) open
C) serial
D) redundant

Question 6

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

Question 7

The ____ encompasses the entire telephone system, from the wires that enter homes and businesses to the network centers that connect different regions of a country.

A) SLIP
B) POTS
C) PPP
D) PSTN

Question 8

ATM is a WAN technology that functions in the Data Link layer.

Question 9

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

A) slicing
B) linking
C) merging
D) bonding

Question 10

A(n) ____ is the place where a telephone company terminates lines and switches calls between different locations.

A) CO
B) EO
C) DO
D) TO

Question 11

____ means that a telephone company connects residential users to its network with fiber-optic cable.

A) OLT
B) FITL
C) PON
D) FITH

Question 12

____ is an updated, digital version of X.25 that also relies on packet switching.

A) DSL
B) ISDN
C) Frame relay
D) ATM

Question 13

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

A) demarcation point
B) NIU (Network Interface Unit)
C) local loop
D) central office

Question 14

WANs typically send data over ____ available communications networks.

A) privately
B) publicly
C) individually
D) serially

Question 15

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

A) 10
B) 12
C) 23
D) 32

Question 16

SONET specifies framing and multiplexing techniques at the Physical layer.

Question 17

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

A) WAN sites
B) WAN links
C) network service providers
D) central offices

Question 18

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

A) terminal adapter
B) DSLAM
C) smart jack
D) terminator

Question 19

A ____ connection is one in which a user connects her computer, via a modem, to a distant network and stays connected for a finite period of time.

A) remote
B) direct
C) dial-up
D) virtual

Question 20

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

A) signal
B) hierarchy
C) channel
D) traffic

Question 21

List and describe the key strengths of SONET.

Question 22

Explain how ATM relies on virtual circuits.

Question 23

A(n) ____________________ node in synchronous communications recognizes that it should be receiving data by looking at the time on the clock.

Question 24

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

Question 25

Explain how a cable modem is utilized in broadband cable connections.

Question 26

Describe the fundamental properties WANs and LANs have in common.

Question 27

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

A) terminal adapter
B) DSLAM
C) smart jack
D) terminator

Question 28

Define and describe a PSTN.

Question 29

Define the term xDSL and name the better known DSL varieties.

Question 30

A(n) ____________________ combines individual SONET signals on the transmitting end, and another multiplexer separates combined signals on the receiving end.

Question 31

What sets ATM apart from Ethernet is its ____ size.

A) channel
B) frame
C) variable packet
D) fixed packet

Question 32

Define a fractional T1 and explain why an organization might implement it.

Question 33

Describe an important difference between frame relay and X.25.

Question 34

____________________ are connections between network nodes that, although based on potentially disparate physical links, logically appear to be direct, dedicated links between those nodes.

Question 35

The data rate of a particular SONET ring is indicated by its ____, a rating that is internationally recognized by networking professionals and standards organizations.

A) OC (Optical Carrier) level
B) CIR (committed information rate)
C) BRI (Basic Rate Interface)
D) DS0 (digital signal, level 0)

Question 36

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

Question 37

At the customer's demarcation point, either inside or outside the building, RJ-48 connectors terminate in a ____.

A) terminal adapter
B) smart jack
C) CSU/DSU
D) switch

Question 38

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

A) throughput
B) low cost
C) fault tolerance
D) latency

Question 39

Broadband cable requires many subscribers to share the same local line, thus raising concerns about ____ and actual (versus theoretical) throughput.

A) access
B) costs
C) noise
D) security

Question 40

Why is SONET technology typically not implemented by small or medium-size businesses?

Question 41

Describe the most important advantage of SONET.