SSD8-1

1.

Which of the following parameters can be specified in the header of a request in the Hypertext Transfer Protocol (HTTP)?

The types of image formats that a browser understands

The type of browser (e.g., Netscape, Internet Explorer) making the request

The method by which the request is to be satisfied—for example, whether the request is a GET of a form submission

(a) III only

(b) I, II, and III

(c) II and III only

(d) I and II only

Correct answer is (b)

Your score on this question is: 0.00

Feedback:

See section 1.1.1 of the course notes.

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2.

Which of the following distinguish stream sockets (e.g., TCP) from datagram sockets (e.g., UDP)?

Stream sockets guarantee delivery of the data sent through them.

Stream sockets can be used to send application data to a remote host, whereas datagram sockets can only send control commands.

Stream sockets have greater overhead.

(a) I and III only

(b) I and II only

(c) II and III only

(d) I only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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3.

A computer sends 100 Kbytes of aggregate data to another computer through the network. If this transmission time takes 10 seconds and setup time is negligible, the throughput of this network is

(a) not able to be determined with the information given

(b) exactly 10 Kbps

(c) in the range from 60 to 120 Kbps (kilobits per second)

(d) in the range from 6 to 12 Kbps (kilobits per second)

Correct answer is (c)

Your score on this question is: 0.00

Feedback:

See section 1.1.4 of the course notes.

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4.

An application on a computer sends data through a socket to another computer. Which of the following are specified by the communication protocol?

The contents of the message body

The speed of transmission

The header format, which specifies the header field sizes and meanings

(a) II and III only

(b) III only

(c) I only

(d) I and III only

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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5.

An advantage of defining network protocols through agreement among many companies and individuals is that

(a) different implementations can then communicate with each other

(b) otherwise source code would need to be shipped with all networking applications

(c) only one implementation need then be created

(d) a protocol designed by committee always has better performance than that designed by a single company or research project

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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6.

We send a packet from host A to host B, which immediately acknowledges it. We measure the interval between the time the packet is sent by A and its acknowledgement is received. This interval is found to be 180 milliseconds. What can be said about the latency of the link from A to B?

(a) It is smaller than 180 ms.

(b) It is greater than 180 ms.

(c) It is exactly 180 ms.

(d) It is exactly 90 ms.

Correct answer is (a)

Your score on this question is: 0.00

Feedback:

See section 1.1.4 of the course notes.

(d) This would be so only if the latency in the direction A->B was identical to the latency in the direction B->A

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7.

What can be said about the protocol used by the implementation of the transport layer of an Internet host?

It guarantees delivery.

It is the Transmission Control Protocol (TCP).

It uses services provided by the session layer.

(a) none

(b) I only

(c) I and II only

(d) I and III only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.5 of the course notes.

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8.

Which of the following methods are invoked by a client implemented with sockets?

connect( )

listen( )

read( )

(a) I, II, and III

(b) III only

(c) I only

(d) I and III only

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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9.

When you connect your computer to the Internet, the protocol(s) your computer uses is (are) selected according to

(a) the application client and server you use at each moment

(b) which HTTP (Web) server you connect to

(c) which operating system is running on your computer

(d) what vendor your Internet service provider purchased equipment from

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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10.

Which of the following activities use an inter-network?

A phone call from Pittsburgh in the United States to Chennai in India

A phone call from a wired phone to a mobile ("cell") phone

A chat session between two computers connected to an office Ethernet

(a) I, II, and III

(b) I only

(c) I and II only

(d) III only

Correct answer is (c)

Your score on this question is: 0.00

Feedback:

See section 1.1.6 of the course notes.

1.

An advantage of defining network protocols through agreement among many companies and individuals is that

(a) only one implementation need then be created

(b) a protocol designed by committee always has better performance than that designed by a single company or research project

(c) otherwise source code would need to be shipped with all networking applications

(d) different implementations can then communicate with each other

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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2.

Packet collisions occur in an Ethernet network because

(a) the Ethernet switching mechanism may occasionally send two packets through the same route

(b) two different Ethernet networks may be spliced together

(c) two Ethernet nodes can send packets at the same time

(d) the Ethernet uses a ring topology

Correct answer is (c)

Your score on this question is: 0.00

Feedback:

See section 1.1.2 of the course notes.

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3.

The Maximum Transfer Unit (MTU) is a parameter of

(a) the technology of the physical network

(b) the application protocol

(c) the size of data sent by the application

(d) the operating system

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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4.

Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination

(a) in the order A-B, after possibly having traversed different routes

(b) in the order A-B, after having traversed the same route

(c) in any order, after having traversed the same route

(d) in any order, after possibly having traversed different routes

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.2 of the course notes.

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5.

Ethernet (IEEE 802.3) is an example of

(a) a successful example of the Internet's strategy of developing standards through "rough consensus and running code"

(b) an a priori standard

(c) a de facto standard later developed into a de jure standard

(d) a standard developed by the International Telecommunications Union

Correct answer is (c)

Your score on this question is: 0.00

Feedback:

See section 1.1.6 of the course notes.

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6.

In a broadcast network

(a) only the destination computer sees a packet

(b) only the computers that are tuned to a channel see and process the packets in that channel

(c) all computers see and process the application data within all packets

(d) all computers see all packets, but the application data in each packet is only processed by the destination computer

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.1 of the course notes.

(b) A network with channels would be, in effect, multiple broadcast networks.

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7.

The transmission of high-quality, interactive voice and video over the current Internet is difficult because today's Internet

(a) gives higher priority to bulk data transfers

(b) is unable to guarantee minimum throughput or maximum latency for a given connection

(c) does not really have sufficient throughput

(d) uses connectionless protocols

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

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8.

What can be said concerning the protocol that is used by the implementation of the network layer of an Internet host?

It guarantees delivery.

It is the Internet Protocol (IP).

It uses services provided by the session layer.

(a) none

(b) I and II only

(c) I only

(d) II only

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.5 of the course notes.

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9.

A computer sends 100 Kbytes of aggregate data to another computer through the network. If this transmission time takes 10 seconds and setup time is negligible, the throughput of this network is

(a) exactly 10 Kbps

(b) in the range from 60 to 120 Kbps (kilobits per second)

(c) not able to be determined with the information given

(d) in the range from 6 to 12 Kbps (kilobits per second)

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

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10.

Why do network applications send "messages," but the network transmits information in "packets?"

Buffer allocation and error handling is easier when done for smaller chunks of data.

Multiple messages can be sent in a single large packet to decrease overhead.

Network engineers and application programmers just use different terminology for the same unit of application data.

A message needs to be packaged with the instructions to process it at the destination.

(a) II and IV only

(b) II and III only

(c) I and II only

(d) I, II, III, and IV

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

1.

An advantage of defining network protocols through agreement among many companies and individuals is that

(a) different implementations can then communicate with each other

(b) only one implementation need then be created

(c) otherwise source code would need to be shipped with all networking applications

(d) a protocol designed by committee always has better performance than that designed by a single company or research project

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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2.

The Protocol Data Unit (PDU) that is sent by a protocol layer to its peer on the destination system typically includes

A payload

A protocol header

A router vendor ID

(a) II only

(b) I and III only

(c) I, II, and III

(d) I and II only

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.5 of the course notes.

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3.

How does an operating system identify the application to which data coming in from the network should be relayed?

(a) By the file extension of the data

(b) Only one application at a time is given access to the network.

(c) By the protocol with which the data was sent

(d) By the port number carried by the transport protocol

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.1 of the course notes.

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4.

Which of the following distinguish stream sockets (e.g., TCP) from datagram sockets (e.g., UDP)?

Stream sockets guarantee delivery of the data sent through them.

Stream sockets can be used to send application data to a remote host, whereas datagram sockets can only send control commands.

Stream sockets have greater overhead.

(a) I only

(b) I and III only

(c) I and II only

(d) II and III only

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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5.

Why do network applications send "messages," but the network transmits information in "packets?"

Buffer allocation and error handling is easier when done for smaller chunks of data.

Multiple messages can be sent in a single large packet to decrease overhead.

Network engineers and application programmers just use different terminology for the same unit of application data.

A message needs to be packaged with the instructions to process it at the destination.

(a) I and II only

(b) II and IV only

(c) I, II, III, and IV

(d) II and III only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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6.

A computer sends 100 Kbytes of aggregate data to another computer through the network. If this transmission time takes 10 seconds and setup time is negligible, the throughput of this network is

(a) exactly 10 Kbps

(b) in the range from 6 to 12 Kbps (kilobits per second)

(c) in the range from 60 to 120 Kbps (kilobits per second)

(d) not able to be determined with the information given

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

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7.

The Maximum Transfer Unit (MTU) is a parameter of

(a) the operating system

(b) the technology of the physical network

(c) the size of data sent by the application

(d) the application protocol

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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8.

Packet collisions occur in an Ethernet network because

(a) the Ethernet switching mechanism may occasionally send two packets through the same route

(b) the Ethernet uses a ring topology

(c) two Ethernet nodes can send packets at the same time

(d) two different Ethernet networks may be spliced together

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 1.1.2 of the course notes.

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9.

What can be said about the protocol used by the implementation of the transport layer of an Internet host?

It guarantees delivery.

It is the Transmission Control Protocol (TCP).

It uses services provided by the session layer.

(a) none

(b) I only

(c) I and III only

(d) I and II only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.5 of the course notes.

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10.

Which of the following methods are invoked by a server implemented with sockets?

connect( )

listen( )

accept( )

(a) I, II, and III

(b) II and III only

(c) II only

(d) III only

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

1.

In contrast to standards developed by traditional standards organizations like the International Telecommunications Union (ITU) or the International Standards Organization (ISO), standards developed by the Internet Engineering Task Force (IETF) can be

(a) modified arbitrarily by the Advance Research projects Agency (ARPA) of the United States Department of Defense, which originally developed the Internet

(b) applied before they have been embodied in working implementations, in order not to delay progress

(c) developed in secret by the members of the IETF until the standards mature sufficiently to withstand public criticism

(d) extensively critiqued and modified by individuals, without requiring them to have special membership status

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

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2.

John is using his bank's Web server to pay his telephone bill electronically. Which kind(s) of network interaction take(s) place in this Scenario, from the moment John logs into his bank's Web site until the telephone company receives the money?

People-people

People-computer

Computer-computer

(a) III only

(b) I, II, and III

(c) II only

(d) II and III only

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1 of the course notes.

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3.

Which of the following activities use an inter-network?

A phone call from Pittsburgh in the United States to Chennai in India

A phone call from a wired phone to a mobile ("cell") phone

A chat session between two computers connected to an office Ethernet

(a) III only

(b) I only

(c) I and II only

(d) I, II, and III

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

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4.

A packet with no data is sent from host A to host B on an otherwise idle network. The packet is found to have taken 35 milliseconds to reach B. The incremental overhead to send an additional byte (usually called the "throughput") is estimated to be five microseconds by repeatedly measuring the transmission times of long packets. Approximately, how long will an eight Kbytes (8192 bytes) packet take to reach B when sent from A?

(a) 76 milliseconds

(b) 40 milliseconds

(c) 55 milliseconds

(d) cannot be determined from the information given

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

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5.

Two packets A and B are sent in that order through a connection-oriented communication network. They could arrive at the destination

(a) only in the order A-B, after having traversed the same route

(b) only in the order A-B, after possibly having traversed different routes

(c) in any order, after having traversed the same route

(d) in any order, after possibly having traversed different routes

Correct answer is (a)

Your score on this question is: 0.00

Feedback:

See section 1.1.2 of the course notes.

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6.

The throughput of a network link for an HTTP session is measured in two ways. Measurement A is the total amount of data received by the browser, divided by the duration of the session. Measurement B is the total amount of data received by the operating system on behalf of the browser, divided by the duration of the session. Which of the following statements about A and B is true?

(a) A is smaller than B

(b) B is equal to A

(c) B and A are not related

(d) B is smaller than A

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

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7.

What can be said concerning the protocol that is used by the implementation of the network layer of an Internet host?

It guarantees delivery.

It is the Internet Protocol (IP).

It uses services provided by the session layer.

(a) none

(b) I only

(c) I and II only

(d) II only

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.5 of the course notes.

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8.

The Internet received its name in the 1980s because

(a) it consisted of many interconnected networks

(b) it was meant to be a network internal to the United States Department of Defense

(c) it achieved international scope with the addition of the City University of London

(d) it was an interim (temporary) design of what it later became, but the name stuck

Correct answer is (a)

Your score on this question is: 0.00

Feedback:

See section 1.1.6 of the course notes.

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9.

Which of the following methods are invoked by a server implemented with sockets?

connect( )

listen( )

accept( )

(a) I, II, and III

(b) III only

(c) II and III only

(d) II only

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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10.

In a broadcast network

(a) only the destination computer sees a packet

(b) all computers see all packets, but the application data in each packet is only processed by the destination computer

(c) only the computers that are tuned to a channel see and process the packets in that channel

(d) all computers see and process the application data within all packets

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

1.

Every Protocol Data Unit (PDU) that is sent by a protocol layer to its remote peer on the destination system always includes:

The headers for all the protocols of the layers above it

The headers for the protocol of the layer below it

Application Data

(a) I, II, and III

(b) I and III only

(c) III only

(d) None

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.5 of the course notes.

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2.

Two packets A and B are sent in that order through a connection-oriented communication network. They could arrive at the destination

(a) only in the order A-B, after possibly having traversed different routes

(b) in any order, after having traversed the same route

(c) in any order, after possibly having traversed different routes

(d) only in the order A-B, after having traversed the same route

Correct answer is (d)

Your score on this question is: 0.00

Feedback:

See section 1.1.2 of the course notes.

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3.

When you connect your computer to the Internet, the protocol(s) your computer uses is (are) selected according to

(a) what vendor your Internet service provider purchased equipment from

(b) which operating system is running on your computer

(c) which HTTP (Web) server you connect to

(d) the application client and server you use at each moment

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

--------------------------------------------------------------------------------

4.

How does an operating system identify the application to which data coming in from the network should be relayed?

(a) By the file extension of the data

(b) By the port number carried by the transport protocol

(c) By the protocol with which the data was sent

(d) Only one application at a time is given access to the network.

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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5.

You have recently become the first network engineer of a large corporation with offices worldwide. The company is considering the installation of a data network, but the Board of Directors is rather old-fashioned and does not see the need to change the company's time-honored business practices. Your first task at the job is to justify your salary and the cost of a new network, and for this purpose you are about to give a presentation to the Board of Directors. Which of the following would you include in your presentation? Assume the directors are extremely intelligent, though perhaps not knowledgeable in your field.

Lower expenditures on computer hardware

Higher availability of customer services

Better protection of the company's proprietary information

(a) I and II only

(b) I and III only

(c) II and III

(d) II only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1 of the course notes.

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6.

Which of the following methods are invoked by a server implemented with sockets?

connect( )

listen( )

accept( )

(a) II and III only

(b) II only

(c) I, II, and III

(d) III only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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7.

Which of the following activities use an inter-network?

A phone call from Pittsburgh in the United States to Chennai in India

A phone call from a wired phone to a mobile ("cell") phone

A chat session between two computers connected to an office Ethernet

(a) III only

(b) I and II only

(c) I only

(d) I, II, and III

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

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8.

Ethernet (IEEE 802.3) is an example of

(a) an a priori standard

(b) a de facto standard later developed into a de jure standard

(c) a successful example of the Internet's strategy of developing standards through "rough consensus and running code"

(d) a standard developed by the International Telecommunications Union

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

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9.

Packet collisions occur in an Ethernet network because

(a) the Ethernet switching mechanism may occasionally send two packets through the same route

(b) the Ethernet uses a ring topology

(c) two different Ethernet networks may be spliced together

(d) two Ethernet nodes can send packets at the same time

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.2 of the course notes.

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10.

A packet with no data is sent from host A to host B on an otherwise idle network. The packet is found to have taken 35 milliseconds to reach B. The incremental overhead to send an additional byte (usually called the "throughput") is estimated to be five microseconds by repeatedly measuring the transmission times of long packets. Approximately, how long will an eight Kbytes (8192 bytes) packet take to reach B when sent from A?

(a) 76 milliseconds

(b) cannot be determined from the information given

(c) 40 milliseconds

(d) 55 milliseconds

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

1.

Which of the following distinguish stream sockets (e.g., TCP) from datagram sockets (e.g., UDP)?

Stream sockets guarantee delivery of the data sent through them.

Stream sockets can be used to send application data to a remote host, whereas datagram sockets can only send control commands.

Stream sockets have greater overhead.

(a) I and III only

(b) I only

(c) II and III only

(d) I and II only

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

--------------------------------------------------------------------------------

2.

Ethernet (IEEE 802.3) is an example of

(a) a standard developed by the International Telecommunications Union

(b) a successful example of the Internet's strategy of developing standards through "rough consensus and running code"

(c) an a priori standard

(d) a de facto standard later developed into a de jure standard

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

--------------------------------------------------------------------------------

3.

The Internet received its name in the 1980s because

(a) it consisted of many interconnected networks

(b) it was an interim (temporary) design of what it later became, but the name stuck

(c) it achieved international scope with the addition of the City University of London

(d) it was meant to be a network internal to the United States Department of Defense

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.6 of the course notes.

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4.

Which of the following are specified by the HTTP protocol?

The syntax of the request header

The syntax of the response header

The specific legal names of the request header fields

(a) I and II only

(b) I and III only

(c) I only

(d) I, II, and III

Correct answer is (a)

Your score on this question is: 0.00

Feedback:

See section 1.1.1 of the course notes.

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5.

Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination

(a) in any order, after possibly having traversed different routes

(b) in the order A-B, after having traversed the same route

(c) in the order A-B, after possibly having traversed different routes

(d) in any order, after having traversed the same route

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.2 of the course notes.

--------------------------------------------------------------------------------

6.

The Maximum Transfer Unit (MTU) is a parameter of

(a) the application protocol

(b) the technology of the physical network

(c) the operating system

(d) the size of data sent by the application

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

--------------------------------------------------------------------------------

7.

A packet with no data is sent from host A to host B on an otherwise idle network. The packet is found to have taken 35 milliseconds to reach B. The incremental overhead to send an additional byte (usually called the "throughput") is estimated to be five microseconds by repeatedly measuring the transmission times of long packets. Approximately, how long will an eight Kbytes (8192 bytes) packet take to reach B when sent from A?

(a) 40 milliseconds

(b) 76 milliseconds

(c) 55 milliseconds

(d) cannot be determined from the information given

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 1.1.4 of the course notes.

--------------------------------------------------------------------------------

8.

Two packets A and B are sent in that order through a connection-oriented communication network. They could arrive at the destination

(a) only in the order A-B, after having traversed the same route

(b) in any order, after having traversed the same route

(c) only in the order A-B, after possibly having traversed different routes

(d) in any order, after possibly having traversed different routes

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 1.1.2 of the course notes.

--------------------------------------------------------------------------------

9.

Why do network applications send "messages," but the network transmits information in "packets?"

Buffer allocation and error handling is easier when done for smaller chunks of data.

Multiple messages can be sent in a single large packet to decrease overhead.

Network engineers and application programmers just use different terminology for the same unit of application data.

A message needs to be packaged with the instructions to process it at the destination.

(a) II and III only

(b) I, II, III, and IV

(c) II and IV only

(d) I and II only

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 1.1.1 of the course notes.

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10.

An application on a computer sends data through a socket to another computer. Which of the following are specified by the communication protocol?

The contents of the message body

The speed of transmission

The header format, which specifies the header field sizes and meanings

(a) III only

(b) I and III only

(c) I only

(d) II and III only

Correct answer is (a)

Your score on this question is: 0.00

Feedback:

See section 1.1.1 of the course notes.

(b) The protocol specifies how to transmit the contents, but not what the contents are.

1.

Which of the following functions can the transport layer provide to applications?

End-to-end flow control

Packet forwarding

Congestion control

(a) I only

(b) I and III only

(c) II and III only

(d) I, II, and III

Correct answer is (b)

Your score on this question is: 10.00

Feedback:

See section 2.1.1 of the course notes.

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2.

The Pittsburgh Supercomputing Center and the San Diego Supercomputing Center are linked to the Internet via very high-speed lines (in 1999, about 622 Mbps). Separated by about 4,000 Km, and several routers, the network installers measured the round trip time between these two sites to be about 50 milliseconds. You want to exchange a large data set between two very fast computers at these sites. The physical network capacity and/or speed of the computers limit the maximum TCP throughput to be about 50 million bytes per second under ideal circumstances. Assuming the channel is free of interference and that very few packets, if any, are dropped, how much memory would you allocate for a TCP connection at the sender in order to maximize throughput without spending money unnecessarily?

(a) none

(b) as much as possible

(c) a few megabytes

(d) a few kilobytes, enough to hold one packet and one acknowledgment

Correct answer is (c)

Your score on this question is: 10.00

Feedback:

See section 2.1.1 of the course notes.

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3.

You have just written an implementation of a transport protocol. You have aggressively pursued performance. For example, all acknowledgments are piggybacked on top of regular data packets, in order to minimize their overhead. When your company releases your product, however, you get the following complaint:

(a) Many packets are retransmitted many times even though the network is idle.

(b) ARP responses take a lot longer than before.

(c) Packet headers have doubled in size, thereby halving the expected performance gains.

(d) Many more packets than before fail to reach the receiving host.

Correct answer is (a)

Your score on this question is: 10.00

Feedback:

See section 2.1.3 of the course notes.

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4.

What is the service that TCP provides but UDP does not?

(a) Error detection using checksum

(b) API provided to application layer

(c) Addressing

(d) Congestion control

Correct answer is (d)

Your score on this question is: 10.00

Feedback:

See section 2.1.3 of the course notes.

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5.

A transport protocol entity determines that the underlying network is able to deliver 100 of its packets every second. Each of these packets contains 1,500 bytes (including transport headers). In addition, the time elapsed between the transmission of a packet and the reception of its acknowledgement is 3 seconds on the average. An efficient and smooth flow would require that the sliding window size be no less than approximately

(a) 300 packets

(b) 34 packets

(c) 600 packets

(d) 100 packets

Correct answer is (a)