Problem Session

Sniffer

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netboys/index.htm

Problems

1) The ________ model shows how the network functions of a computer ought to be organized.A) ITU-T B) OSI C) ISO D) ANSI

2) The OSI model consists of ________ layers. A) three B) five C) seven D) eight

3) The ________ layer decides the location of synchronization points. A) network B) transport C) sessionD) presentation

4) The ________ layer is the layer closest to the transmission medium.A) physical B) data link C) network

D) transport

5) In the _________ layer, the data unit is called a frame.A) physical B) data link C)

network D) transport

6) When different programs are running at the same time on a computer, they can be identified by their _________ addresses.A) node B) station C) service point (port)D) source

7) Decryption and encryption of data are the responsibility of the _______ layer. A) physical B) data link C) presentationD) session

8) Node-to-node delivery of the data unit is the responsibility of the _______ layer.A) physical B) data link C) transport

D) network

9) As the data packet moves from the lower to the upper layers, headers are ________.A) added B) subtracted C)rearranged

D) modified

10) As the data packet moves from the upper to the lower layers, headers are ________.A) added B) removed C) rearranged

D) modified

11) The ________ layer lies between the network layer and the session layer. A) physical B) data link C) transport

D) presentation

12) Layer 2 lies between the physical layer and the _______ layer.A) network B) data link C) transport

D) presentation

13) When data are transmitted from device A to device B, the header from A’s layer 5 is read by B’s ________ layer.

A) physical B) transport C) sessionD) presentation

14) In the ________ layer, translations from one character code to another occur.A) transport B) session C) presentationD) application

15) The ________ layer changes bits into electromagnetic signals. A) physical B) data link C) transport

D) presentation

16) The ________ layer can use the trailer of the frame for error detection.A) physical B) data link C) transport

D) presentation

17) How are OSI and ISO related to each other?

18) Match the following to one or more layers of the seven OSI layers:A) route determinationB) flow controlC) access to the network for the end userD) formatting data from one code to anotherE) switching

19) Match the following to one or more of the seven OSI layers:A) provides reliable end-to-end transmission of entire

message B) defines framesC) provides user services such as electronic mail and file transferD) transmits signals across physical medium

20) Match the following to one or more of the seven OSI layers:A) direct communication with user’s application

program B) error correction and retransmissionC) mechanical, electrical, and functional interfaceD) responsibility for node-to-node delivery of a frameE) reassembly of data packets into a message

21) Match the following to one or more of the seven OSI layers:A) provides format and code conversion services

B) establishes, manages, and terminates sessionsC) oversees end-to-end transmission of data packetsD) provides verification of log-in and log-outE) provides independence from differences in data representation

22) Compare and contrast the delivery of data units in the data link layer, the network layer, and the transport layer.

23) The secondary device in a multipoint configuration sends data in response to ___________. A) an ACK B) an ENQ C) a pollD) a SEL

24) In sliding window flow control, if the window size is 63, what is the range of sequence numbers? A) 0 to 63 B) 0 to 64 C) 1 to 63D) 1 to 64

25) In sliding window flow control, the frames to the left of the receiver window are frames __________.A) received but not acknowledgedB) received and acknowledgedC) not received D) not sent

26) Regulation of the rate of transmission of data frames is known as _________. A) line discipline B) flow disciplineC) data rate control D) switch control

27) The retransmission of damaged or lost frames in the data link layer is known as _________.A) error control B) error conditioningC) line discipline D) flow control

28) Flow control is needed to prevent ___________.A) bit errors B) overflow of the sender bufferC) overflow of the receiver bufferD) collision between sender and receiver

29) In go-back-n ARQ, if frames 4, 5, and 6 are received successfully, the receiver may send an ACK ________ to the sender.A) 5 B) 6 C) 7 D) any of the above

30) For a sliding window of buffer size n, there can be a maximum of _________ frames sent but unacknowledged.A) 0 B) n-1 C) n D) n+1

31) An ACK 3 is sliding window flow control (window size of 8) means that frame _________ is next expected by the receiver. A) 2 B) 3 C) 4 D) 8

32) In stop-and-wait ARQ, if data 1 has an error, the receiver sends a _________ frame.A) NAK 0 B) NAK 1 C) NAK 2D) NAK

33) In ________ ARQ, when a NAK is received, all frames sent since the last frame acknowledged are retransmitted.A) stop-and-wait B) go-back-nC) selective-reject D) a and b

34) In _______ ARQ, if a NAK is received, only the specific damaged or lost frame is retransmitted.A) stop-and-wait B) go-back-nC) selective-reject D) a and b

35) ARQ stands for ________.A) automatic repeat quantization B) automatic repeat requestC) automatic retransmission requestD) acknowledge repeat request

36) Draw the sender and receiver windows for a system using go-back-n ARQ given the following:A) frame 0 is sent; frame 0 is acknowledgedB) frames 1 and 2 are sent; frames 1 and 2 are acknowledgedC) frames 3, 4, and 5 are sent; NAK 4 is receivedD) frames 4, 5, and 6 are sent; frames 4 through 7 are acknowledged.

37) Repeat problem 48 using selective-reject ARQ.

38) What does the number on a NAK frame mean for: A) stop-and-wait ARQ? B) go-back-n ARQ? C) selective-reject ARQ?

39) What does the number on an ACK frame mean for:A) stop-and-wait ARQ? B) go-back-n

ARQ? C) selective-reject ARQ?

40) ACK 7 has been received by the sender in a sliding window system. Now frames 7, 0, 1, 2, and 3 are sent. For each of the following separate scenarios, discuss the significance of the receiving of:A) an ACK 1 B) an ACK 4C) an ACK 3 D) a NAK 1E) a NAK 3 E) a NAK 7

41) End-to-end delivery is the movement of a message from _______.A) one station to the next stationB) one network to the next networkC) source to destination D) non of the above

42) What type of addressing is specifically used by the transport layer?A) station addresses B) network addressesC) application program port addressesD) dialog addresses

43) In ________ services, connections must be established and terminated.A) connectionless B) connection-oriented

C) segmentation D) none of the above

44) In ________ services, no connection establishment is needed. A) connectionless B) connection-oriented

C) segmentation D) none of the above

45) A virtual circuit is associated with a _________ service.A) connectionless B) connection-oriented

C) segmentation D) none of the above

46) In _________ services, packets of a single transmission travel from source to destination via different paths. A) connectionless B) connection-oriented C) segmentation D) none of the above

47) Show by calculation how many networks (not hosts) each IP address class (A, B, and C only) can have.

48) Show by calculation how many hosts per network each IP address class (A, B, and C only) can have.

49) Write the binary form of the following internet addresses:A) 124.34.6.9 B) 23.67.6.3C) 0.23.56.0 D) 12.34.67.125

50) Find the class of the following host addresses:A) 121.56.3.67 B) 193.23.56.23C) 231.23.67.123 D) 142.23.56.23

51) Find the network address of each host address in the preceding problem.

52) Draw an internet with the following specifications. Show all of the hosts, their addresses, and connections. The address selection is up to you. A) one token ring network with four hosts (Class A)B) one Ethernet with four hosts (Class C)C) the token ring is connected to the Ethernet by a gateway