Deck 9: Wide Area Networks

Question 1

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

Answer 1

False

Question 2

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

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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

Question 5

Frame relay is a reliable packet service.

Question 6

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

Question 7

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

Question 8

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

Question 9

A T1 circuit provides a data rate of 1.544Mbps.

Question 10

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

Question 11

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

Question 12

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

Question 13

Full mesh networks are inexpensive.

Question 14

Datagrams are connection-oriented.

Question 15

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

Question 16

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

Question 17

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

Question 18

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

Question 19

Ethernet services are now being successfully used in WAN environments.

Question 20

`
T carrier circuits can only be used to transmit voice.

Question 21

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

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

Question 22

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 23

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 24

An intranet VPN connects different organizations over the Internet.

Question 25

_____ 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 26

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 27

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 28

A ___________ is a device that permits a customer to connect to a digital T-carrier service.

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

Question 29

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 30

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 31

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 32

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

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

Question 33

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 34

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 35

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 36

MPLS operate at layer 4.

Question 37

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 38

VPNs offer high security because they operate through the Internet.

Question 39

Mesh networks:

A)usually provide relatively long routes through the network (compared to ring networks))
B)typically contain more circuits in the network than in star or ring networks
C)do not use decentralized routing
D)typically are less expensive than ring networks
E)do not have many possible routes through the network to prevent one circuit from becoming overloaded

Question 40

____________ 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 41

_____________ is sometimes called a Layer 2.5 technology.

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

Question 42

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 43

_____________ 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 44

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

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

Question 45

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 46

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 47

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)does not add to the network traffic and should be used in all network environments
E)is another term for static routing in WANs

Question 48

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 49

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 50

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 51

Which of the following is a primary advantage of a VPN in comparison to a private WAN connection?

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

Question 52

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 53

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 54

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 55

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 56

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 57

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 which you wish to transmit and receive 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 58

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 59

______________ are sometimes called private line services.

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

Question 60

SONET:

A)is a standard for optical transmission that currently operates at Terabit per second speeds
B)is almost identical to the ITU-T standard, synchronous digital hierarchy (SDH))
C)uses existing copper cabling and the PSTN network
D)refers to Sprint Overall Network
E)is not currently available, even in large cities

Question 61

Where does packetizing take place?

Question 62

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

Question 63

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

Question 64

Explain the differences between CIR and MAR.

Question 65

Describe the three types of VPN.

Question 66

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 67

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

Question 68

What are the main benefits of using a VPN?

Question 69

Which WAN technology is designed to work with a variety of commonly used layer-2 protocols and is sometimes called a layer-2.5 technology because it inserts a 4-byte header that contains its own information between the layer-2 frame and the layer-3 IP packet?.

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

Question 70

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

Question 71

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

Question 72

How does a SVC differ from a PVC?

Question 73

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

Question 74

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