NET 110 Chapter 7 – Flashcards

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false
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(T/F) 1. In a star topology, a single connection failure will halt all traffic between all sites.
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true
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(T/F) 2. Dial-up ISDN does not convert a computer's digital signals to analog before transmitting them over the PSTN.
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true
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(T/F) 3. ATM is a WAN technology that functions in the Data Link layer.
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true
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(T/F) 4. SONET specifies framing and multiplexing techniques at the Physical layer.
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false
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(T/F) 5. After SONET, BPL has the best maximum throughput available.
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publicly
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1. WANs typically send data over ____ available communications networks.
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WAN sites
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2. The individual geographic locations connected by a WAN are known as ____.
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nonroutable
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3. Because WAN connections require routers or other Layer 3 devices to connect locations, their links are not capable of carrying ____ protocols.
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redundant
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4. On most modern WANs, a ring topology relies on ____ rings to carry data.
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mesh
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5. ____ WANs are the most fault-tolerant type of WAN because they provide multiple routes for data to follow between any two points.
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PSTN (public switched telephone network)
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6. 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.
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CO (central office)
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7. A(n) ____ is the place where a telephone company terminates lines and switches calls between different locations.
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dial-up
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8. 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.
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local loop/last mile
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9. The portion of the PSTN that connects any residence or business to the nearest CO is known as the ____.
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FTTH (fiber to the home)
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10. ____ means that a telephone company connects residential users to its network with fiber-optic cable.
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frame relay
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11. ____ is an updated, digital version of X.25 that also relies on packet switching.
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bonding
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12. In a process called ____, two 64-Kbps ISDN B channels can be combined to achieve an effective throughput of 128 Kbps.
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(TA) terminal adapter
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13. A ____ converts digital signals into analog signals for use with ISDN phones and other analog devices.
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23
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14. ISDN PRI uses ____ B channels and one 64-Kbps D channel.
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signal
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15. The speed of a T-carrier depends on its ____ level.
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smart jack
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16. At the customer's demarcation point, either inside or outside the building, RJ-48 connectors terminate in a ____.
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DSLAM (DSL access multiplexer)
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17. A ____ aggregates multiple DSL subscriber lines and connects them to the carrier's CO.
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security
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18. Broadband cable requires many subscribers to share the same local line, thus raising concerns about ____ and actual (versus theoretical) throughput.
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fixed packet
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19. What sets ATM apart from Ethernet is its ____ size.
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fault tolerant
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20. SONET's extraordinary ____ results from its use of a double-ring topology over fiber-optic cable.
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OC (optical carrier)
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21. The data rate of a particular SONET ring is indicated by its ____, a rating that is internationally recognized by networking professionals and standards organizations.
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virtual circuits
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1. ____________________ are connections between network nodes that, although based on potentially disparate physical links, logically appear to be direct, dedicated links between those nodes.
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T-carrier
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2. A(n) ____________________ uses TDM (time division multiplexing) over two wire to divide a single channel into multiple channels.
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receiving
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3. A(n) ____________________ node in synchronous communications recognizes that it should be receiving data by looking at the time on the clock.
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multiplexer
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4. A(n) ____________________ combines individual SONET signals on the transmitting end, and another multiplexer separates combined signals on the receiving end.
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LANE (LAN emulation)
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5. ____________________ encapsulates incoming Ethernet or token ring frames, then converts them into ATM cells for transmission over an ATM network.
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tiered topology
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1. 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.
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downstream
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2. Occurs when data travels from the carrier's switching facility to the customer.
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star topology
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3. Contains a single site acting as the central connection point for several other points.
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asymmetrical communications
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4. Occurs when downstream throughput is higher than upstream throughput.
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signal level
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5. Refers to the T-carrier's Physical layer electrical signaling characteristics as defined by ANSI standards in the early 1980s.
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upstream
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6. Occurs when data travels from the customer to the carrier's switching facility.
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bus topology
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7. Occurs when each site is directly connected to no more than two other sites in a serial fashion.
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symmetrical technology
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8. Provides equal capacity for data traveling both upstream and downstream.
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mesh topology
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9. Incorporates many directly interconnected sites.
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--enable communication between clients and hosts for resource sharing. --same protocols from Layers 3 and higher --carry digitized data via packet-switched connections.
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1. Describe the fundamental properties WANs and LANs have in common.
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The network of lines and carrier equipment that provides telephone service to most homes and businesses with digital transmission.
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2. Define and describe a PSTN.
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X.25 is analog and frame relay is digital.
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3. Describe an important difference between frame relay and X.25.
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An arrangement that allows a customer to lease only some of the channels on a T1 line. They may expect their traffic to grow and that may require a full T1 eventually, but can't currently justify leasing a full T1.
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4. Define a fractional T1 and explain why an organization might implement it.
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The term xDSL refers to all DSL varieties. -ADSL -G.Lite -HDSL -SHDSL -SDSL -VDSL
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5. Define the term xDSL and name the better known DSL varieties.
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modulates and demodulates signals via cable. operate at physical and data link layer. connects to PC via RJ-45/USB/wireless or a switch/router.
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6. Explain how a cable modem is utilized in broadband cable connections.
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it helps ATM maintain point-to-point connection-oriented transmissions
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7. Explain how ATM relies on virtual circuits.
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-can integrate other WAN technologies // can work with different signal types and standards -offers fast data transfer rates //fiber-optics, determined by OC level -allows for simple link additions/removals //multiplexer -provides high degree of fault tolerance //double-ring topology over fiber-optic cable
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8. List and describe the key strengths of SONET.
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interoperability between different signal types and standards
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9. Describe the most important advantage of SONET.
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high cost
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10. Why is SONET technology typically not implemented by small or medium-size businesses?
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