GATE-CS-2014-(Set-1)

Question 31

Consider the following three statements about link state and distance vector routing protocols, for a large network with 500 network nodes and 4000 links.

[S1] The computational overhead in link state protocols 
     is higher than in distance vector protocols.
[S2] A distance vector protocol (with split horizon) 
     avoids persistent routing loops, but not a link
     state protocol.
[S3] After a topology change, a link state protocol 
     will converge faster than a distance vector
     protocol.

Which one of the following is correct about S1, S2, and S3 ?

• S1, S2, and S3 are all true.
• S1, S2, and S3 are all false.
• S1 and S2 are true, but S3 is false
• S1 and S3 are true, but S2 is false

Question 32

Which of the following are used to generate a message digest by the network security protocols?

(P) RSA 
(Q) SHA-1 
(R) DES 
(S) MD5

• P and R only
• Q and R only
• Q and S only
• R and S only

Question 33

Identify the correct order in which the following actions take place in an interaction between a web browser and a web server.

1. The web browser requests a webpage using HTTP.
2. The web browser establishes a TCP connection with the web server.
3. The web server sends the requested webpage using HTTP.
4. The web browser resolves the domain name using DNS.

• 4,2,1,3
• 1,2,3,4
• 4,1,2,3
• 2,4,1,3

Question 34

Consider a token ring network with a length of 2 km having 10 stations including a monitoring station. The propagation speed of the signal is 2 × 10⁸ m/s and the token transmission time is ignored. If each station is allowed to hold the token for 2 μsec, the minimum time for which the monitoring station should wait (in μsec)before assuming that the token is lost is _______.

• 28 to 30
• 20 to 22
• 0 to 2
• 31 to 33

Question 35

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 msec and the maximum segment size used is 2 KB. The time taken (in msec) by the TCP connection to get back to 32 KB congestion window is _________.

• 1100 to 1300
• 800 to 1000
• 1400 to 1600
• 1500 to 1700

Question 36

Consider a selective repeat sliding window protocol that uses a frame size of 1 KB to send data on a 1.5 Mbps link with a one-way latency of 50 msec. To achieve a link utilization of 60%, the minimum number of bits required to represent the sequence number field is ________.

• 3
• 4
• 5
• 6

Question 37

Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item x, denoted by r(x) and w(x) respectively. Which one of them is conflict serializable.

• A
• B
• C
• D

Question 38

Given the following two statements:

  S1: Every table with two single-valued 
      attributes is in 1NF, 2NF, 3NF and BCNF.

  S2: AB->C, D->E, E->C is a minimal cover for 
      the set of functional dependencies 
      AB->C, D->E, AB->E, E->C. 

Which one of the following is CORRECT?

• S1 is TRUE and S2 is FALSE.
• Both S1 and S2 are TRUE.
• S1 is FALSE and S2 is TRUE.
• Both S1 and S2 are FALSE.

Question 39

Consider the following set of processes that need to be scheduled on a single CPU. All the times are given in milliseconds.

Process Name      Arrival Time      Execution Time
    A                  0                  6
    B                  3                  2
    c                  5                  4
    D                  7                  6
    E                  10                 3

Using the shortest remaining time first scheduling algorithm, the average process turnaround time (in msec) is ____________________.

• 7.2

• 8

• 7

• 7.5

Question 40

Assume that there are 3 page frames which are initially empty. If the page reference string is 1, 2, 3, 4, 2, 1, 5, 3, 2, 4, 6, the number of page faults using the optimal replacement policy is__________.

• 5
• 6
• 7
• 8