CS/IT Gate Subject



Computer Network GATE CS and IT previous year questions with Answer


Ques 41 Gate 2015 Set-2

A link has a transmission speed of 106 bits/sec. It uses data packets of size 1000 bytes each. Assume that the acknowledgment has negligible transmission delay, and that its propagation delay is the same as the data propagation delay. Also assume that the processing delays at nodes are negligible. The efficiency of the stop-and-wait protocol in this setup is exactly 25%. The value of the one-way propagation delay (in milliseconds) is ___________.


a is the correct answer.


Ques 42 Gate 2015 Set-2

Which one of the following statements is NOT correct about HTTP cookies?

A

A cookies is a piece of code that has the potential to compromise the security of an Internet user.

B

A cookie gains entry to the user’s work area through an HTTP header.

C

A cookie has an expiry date and time.

D

Cookies can be used to track the browsing pattern of a user at a particular site.



Ques 43 Gate 2015 Set-1

Consider a LAN with four nodes S1, S2, S3 and S4. Time is divided into fixed-size slots, and a node can begin its transmission only at the beginning of a slot. A collision is said to have occurred if more than one node transmit in the same slot. The probabilities of generation of a frame in a time slot by S1, S2, S3 and S4 are 0.1, 0.2, 0.3 and 0.4, respectively. The probability of sending a frame in the first slot without any collision by any of these four stations is_________


a is the correct answer.


Ques 44 Gate 2015 Set-1

Suppose two hosts use a TCP connection to transfer a large file. Which of the following statements is/are False with respect to the TCP connection?

I. If the sequence number of a segment is m, then the sequence number of the subsequent segment is always m+1.
II. If the estimated round trip time at any given point of time is t sec, the value of the retransmission timeout is always set to greater than or equal to t sec.
III. The size of the advertised window never changes during the course of the TCP connection.
IV. The number of unacknowledged bytes at the sender is always less than or equal to the advertised window.


a is the correct answer.


Ques 45 Gate 2015 Set-1

Which one of the following fields of an IP header is NOT modified by a typical IP router?

A

Checksum

B

Source address

C

Time to Live (TTL)

D

Length



Ques 46 Gate 2015 Set-1

Suppose that everyone in a group of N people wants to communicate secretly with the N–1 others using symmetric key cryptographic system. The communication between any two persons should not be decodable by the others in the group. The number of keys required in the system as a whole to satisfy the confidentiality requirement is

A

2N

B

N(N – 1)

C

N(N – 1)/2

D

(N – 1)2



Ques 47 Gate 2015 Set-1

In one of the pairs of protocols given below, both the protocols can use multiple TCP connections between the same client and the server. Which one is that?

A

HTTP, FTP

B

HTTP, TELNET

C

FTP, SMTP

D

HTTP, SMTP