BARC 2020: Computer Networks Nuclear Quiz 2 (App update required to attempt this test) for GATE & PSU CS Exams

Question 1

Consider the following statement about various protocols.

(a) Address resolution protocol is used to get the MAC address when you have their IP address.

(b) Dynamic host configuration protocol is Network layer protocol.

(c) Dynamic host configuration protocol is used to assign the IP address to the host.

(d) Reverse address resolution protocol is used to get the MAC address when you have IP address.

The number of correct statement is ________?

Question 2

Let the size of congestion window of a TCP connection be 32 KB when a timeout occurs. The round trip time of the connection is 100 m sec and the maximum segment size used is 2 KB. The time taken (in m sec) by the TCP connection to get back to 32 KB congestion window is _________.

Question 3

If the UDP header is given as
(FFF0OO35FFEEFFEE)₁₆
Which type of request is made by this UDP header?

Question 4

Consider the two statements regarding Data Link Layer:
Statement 1: Data Link Layer attaches header as well as trailer to the data
Statement 2: Only Error Correcting Codes are attached as trailer at the data link layer
Which of the following is true regarding the above statements?

Question 5

Consider the following plot of TCP window size as a function of time. Assume TCP is operating with slow start , congestion avoidance , fast retransmit and fast recovery mechanism.

What is the time interval where the slow start runs again because of time out and because of 3 ACKS's respectively ?

Question 6

A link has a transmission speed of

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

Question 7

Suppose the maximum Sequence no which is possible with Go-Back N, Stop and Wait and Selective repeat protocol is k. What is the size of Senders window for each protocol respectively?

Question 8

Consider the following statements about the application layer protocols.

a. Telnet protocol is used to communicate with a remote device or system.

b. FTP and POP3 are stateless protocol while HTTP is a stateful protocol.

c. FTP is out of band protocol while HTTP is in-band protocol.

d. HTTP uses port number 80 while SMTP uses port number 20.

Which of the following is correct?

Question 9

Assume out of many stations sharing common channel only two stations transmit frames. If collision occurs both of them uses back-off algorithm to send their frames. What is the probability that they both successfully send their frames in 3^rd round. (Any one of them can send their frames first).

Question 10

Number of keys that are required for secure communication among N persons with symmetric and assymetric key encryption algorithm are?