Deck 9: Wide Area Networks

Question 1

Frame relay is a reliable packet service.

Answer 1

False

Question 2

A T1 circuit provides a data rate of 1.544Mbps.

Answer 2

True

Question 3

A dedicated circuit is usually not available late at nights or on weekends.

Answer 3

False

Question 4

Common carriers sell or lease communication services and facilities to the public.

Question 5

Packet switched networks enable packets from separate messages or separate organizations to be interleaved for transmission.

Question 6

An OC-1 circuit provides a data rate of 155 Mbps.

Question 7

Today, a common carrier that provides long distance services is typically called a local exchange carrier.

Question 8

SONET is made up of very high speed dedicated circuits that incorporate inverse multiplexing IMUX) for all levels above the OC-1 level.

Question 9

A WAN with a ring topology can use full or half duplex circuits

Question 10

Full mesh design networks are more common than partial mesh design networks.

Question 11

In building Wide Area Networks, many organizations do not build their own long distance communication circuits

Question 12

Ethernet/IP packet networks are not provided by common carriers such as AT&T.

Question 13

Full mesh networks are inexpensive.

Question 14

To connect into a packet switched network, a network terminator is generally used.

Question 15

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T carrier circuits can only be used to transmit voice.

Question 16

Virtual private networks permit users to create permanent virtual circuits, or tunnels, through the Internet.

Question 17

The committed information rate CIR) in a permanent virtual circuit is the maximum allowable rate that the network will attempt to provide.

Question 18

Datagrams are connection-oriented.

Question 19

A disadvantage of a star architecture is that the failure of one circuit will disrupt the entire network.

Question 20

WANs can connect BNs across distances that can span up to thousands of miles.

Question 21

The _________________ is a Canadian government agency that regulates voice and data communication.

A)PSTN
B)FCC
C)CRTC
D)CSU
E)POTS

Question 22

A ___________ is/are devices that permit a user to connect to a digital T-carrier service.

A)modem
B)codec
C)CSU/DSU
D)NIC
E)ATM

Question 23

In a ring design WAN,

A)failure in one circuit means that the network can most likely continue to function
B)failure in one circuit always means that the network will cease to function
C)failure in one computer always means that the network will cease to function
D)failure in one circuit means that there will not be any increased traffic delays in the network
E)failure in one computer always means that messages will stop at that computer since it would be impossible to re-route traffic

Question 24

MPLS operate at layer 4.

Question 25

In ______ geometric layout for a network, every computer is connected to every other computer often by point-to-point dedicated circuits.

A)full mesh design
B)ring design
C)star design
D)bus design
E)partial mesh design

Question 26

A star architecture:

A)connects all computers in a closed loop
B)connects all computers off a backbone circuit
C)connects all computers to one central computer that routes messages to the appropriate computer
D)all of the above
E)none of the above

Question 27

In a ring design WAN,

A)messages can take a long time to travel from the sender to the receiver
B)a message arrives at all computers on the network simultaneously
C)messages always arrive faster than in other types of layouts
D)messages are delivered directly from sender to receiver because there is a point-to-point connection directly between each sender and each receiver
E)messages always take one second to travel between sender and receiver

Question 28

Basic rate interface:

A)is typically offered only to commercial customers
B)provides a communications circuit with two 64 Kbps B channels, plus one D channel
C)is defined exactly the same way in Europe
D)has an upper capacity of 1.544 Mbps
E)is comprised of analog circuits only

Question 29

A ________ geometric layout connects all computers in a closed loop, with each computer linked to the next usually with a series of point-to-point dedicated circuits.

A)bus design
B)star design
C)full mesh design
D)ring design
E)partial mesh design

Question 30

Primary rate interface:

A)is typically offered only to commercial customers
B)provides a communications circuit with two 64 Kbps B channels, plus one D channel
C)is defined exactly the same way in Europe
D)has an upper capacity of 128Kbps
E)is comprised of analog circuits only

Question 31

A star topology is:

A)difficult to manage because the central computer receives and routes all messages in the network
B)dependent upon the capacity of the central computer for its performance
C)always slower than a ring network
D)less susceptible to traffic problems than other architectures
E)not affected if the central computer fails

Question 32

_____ are dedicated digital circuits that are the most commonly used form of dedicated circuit services in North America today.

A)Wideband analog services
B)SMDS
C)ATM
D)T-carrier services
E)ISDN

Question 33

Each state or Canadian province has its own ___________ to regulate communications within its borders.

A)CRTC
B)Federal Communications Commission
C)common carriers
D)public utilities commission
E)PTT

Question 34

Mesh networks:

A)usually provide relatively long routes through the network compared to ring networks)
B)require more processing by each computer in the network than in star or ring networks
C)do not use decentralized routing
D)do not have much capacity wasted by network status information
E)do not have many possible routes through the network to prevent one circuit from becoming overloaded

Question 35

An intranet VPN connects different organizations over the Internet.

Question 36

A _______ geometric layout for a WAN connects all computers to one central computer that routes messages to the appropriate computer, usually via a series of point-to-point dedicated circuits.

A)ring design
B)mesh design
C)bus design
D)star design
E)mesh design

Question 37

VPNs offer high security because they operate through the Internet.

Question 38

____________ are companies that build a data and telecommunications infrastructure from which other companies can lease services for WANs and MANs.

A)Common carriers
B)Router manufacturers
C)Standards organizations
D)CSUs
E)PUCs

Question 39

The data rate for a T-1 circuit in North America is:

A)1.544 Mbps
B)6.312 Mbps
C)44.376 Mbps
D)274.176 Mbps
E)1.544 Gbps

Question 40

Which of the following is not a basic architecture for dedicated circuit networks?

A)ring
B)partial mesh
C)bus
D)star
E)full mesh

Question 41

A _________ is a connection-oriented approach to sending packets on a packet switched service.

A)permanent virtual circuit
B)datagram
C)histogram
D)bursty packet
E)fractional T-1 network

Question 42

Which of the following type of networks permit packets from separate messages to be interleaved?

A)circuit switched network
B)dedicated circuit network
C)dial up circuit network
D)packet switched network
E)Fractional T-1 network

Question 43

The performance of WANs can be improved by:

A)upgrading the circuits between the computers
B)increasing the demand placed on the network
C)downgrading the circuits between the computers
D)downgrading the devices that provide access to the circuits
E)increasing network traffic

Question 44

Which of the following is not a benefit of packet switched services?

A)The data transmission rates tend to be lower than dial-up or dedicated circuits.
B)You don't have to set up dedicated circuits between each end point from and to which you wish to transmit data and/or voice.
C)You have the flexibility to send data through a temporary circuit between two connections that will be disconnected as soon as the digital transmission is completed.
D)All circuits are less susceptible to a great deal of noise because they are digital.
E)You don't have to specify all the interconnecting services you need for your WAN when you buy the service.

Question 45

_____________ is sometimes called a Layer 2.5 technology.

A)ATM
B)MPLS
C)Ethernet
D)TCP
E)IP

Question 46

______________ are sometimes called private line services.

A)WANs
B)LANs
C)Circuit-switched networks
D)Dedicated-circuit networks
E)Routed-backbone networks

Question 47

Which of the following is a primary advantage of a VPN?

A)low cost
B)inflexibility
C)unpredictable traffic congestion
D)security
E)complexity to the user

Question 48

In North America, a T1 circuit has ______ 64Kbps channels.

A)2
B)30
C)24
D)12
E)36

Question 49

OC-3072 has a data rate of

A)159.25 Gbps
B)39.813 Gbps
C)1.544 Mbps
D)100 Mbps
E)1.244 Gbps

Question 50

The data rate for a T-3 circuit in North America is:

A)1.544 Mbps
B)6.312 Mbps
C)44.376 Mbps
D)274.176 Mbps
E)1.544 Gbps

Question 51

A _______ is a connectionless method of sending data packets on a packet switched service.

A)bursty packet
B)virtual circuit
C)datagram
D)histogram
E)permanent virtual circuit

Question 52

A _______________ is a particular type of network that uses circuits that run over the Internet but that appears to the user to be a private network.

A)local carrier network
B)virtual private network
C)integrated service digital network
D)software defined network
E)SONET network

Question 53

Ethernet/IP packet networks:

A)are supported with gigabit fiber optic networks in large cities
B)are offered only by the common carriers
C)use token ring layer 2 media access control
D)use IPX/SPX protocols
E)provide CIR up to a maximum of 1.544 Mbps

Question 54

__________ is a term that refers to the speed in converting input packets to output packets.

A)Transfer mode
B)Latency
C)Burstiness
D)Cell relay
E)Frame relay

Question 55

_____________ is a common standard for use by layer 2 access VPNs for encapsulation.

A)L2TP
B)VPN2
C)Encapsule2
D)TCP/IP
E)PPP

Question 56

Which of the following is not a type of VPN?

A)intranet VPN
B)extranet VPN
C)access VPN
D)T-1 VPN
E)a VPN that enables employees to access an organization's network from a remote location

Question 57

SONET:

A)is a standard for optical transmission that currently operates at Terabit per second speeds
B)is very similar to the ITU-T standard, synchronous digital hierarchy
C)uses inverse multiplexing above the OC-1 level
D)refers to Sprint Overall Network
E)is not currently available, even in large cities

Question 58

With a virtual private network, users create permanent virtual circuits through the Internet called:

A)bursts
B)cells
C)tunnels
D)rings
E)clouds

Question 59

In a packet switched network, permanent virtual circuits that look very similar to a _____________ for hardware-based dedicated circuits) move packets through the network.

A)cloud-based ring design
B)cloak-based mesh design
C)cloud-based mesh design
D)common carrier ring design
E)common carrier bus design

Question 60

A _____________ is a user's connection into a packet switched service.

A)packet analog/digital device
B)packet asynchronous/discrete device
C)packet asymmetric/data transmission device
D)packet assembly/disassembly device
E)packet analyzer/decoder device

Question 61

Explain the differences between CIR and MAR.

Question 62

With IP services, the ________ at the sending site takes the outgoing message which usually is an Ethernet frame containing an IP packet), strips off the Ethernet frame and uses the IP address in the IP packet to route the packet though the carrier's packet‐switched network to its final destination.

A)PAD
B)gateway
C)switch
D)router
E)WAN

Question 63

Suppose you joined a company that had a WAN composed of SONET, T carrier services, and frame relay, each selected to match a specific network need for a certain set of circuits.Would you say this was a well-designed network? Explain.

Question 64

Describe the three types of VPN.

Question 65

Where does packetizing take place?

Question 66

Using a chart format, list, define and briefly describe two dedicated circuit services and two packet switched services.

Question 67

Which of the following is not a way to reduce network demand?

A)shifting network usage from high cost times to lower cost times
B)using data compression techniques for all data in the network
C)requiring a network impact statement for all application software developed by the organization
D)moving data further from the applications and people who use them
E)shifting network usage from peak to lower demand times

Question 68

Draw a diagram of packet switched service, and describe packet switching concepts.

Question 69

What are the main benefits of using a VPN?

Question 70

Describe six ways in which a network manager might improve WAN service.

Question 71

How does a SVC differ from a PVC?

Question 72

Dynamic routing:

A)imposes an overhead cost by increasing network traffic
B)decreases performance in networks which have many possible routes
C)decreases performance in networks with "bursty" traffic
D)should be used in 80 to 90 percent of total networks' capacity
E)is another term for static routing in WANs

Question 73

Which of the following is not a key issue to be considered when selecting a WAN service?

A)prestige value of using a particular common carrier
B)flexibility
C)capacity
D)control
E)reliability

Question 74

What are the benefits of IP services over other packet-switched options?

Question 75

Compare the ring, star, and mesh architectures.Provide one example of when each one might be better to use compared to the others.

Question 76

Compare and contrast frame relay, MPLS and Ethernet service networks.

Question 77

Most IP services use _______ as the data link layer protocol.

A)Ethernet
B)TCP
C)MPLS
D)IRoute
E)T1