Unit 9: Data Communication and Computer Networks · 17 questions · about 20 minutes. Press End Mock any time to see your score and the correct answers.
Directions (Q96–100): An IP datagram has arrived with the following partial header information (in hexadecimal): 45000054 00030000 2006…
Correct answer: C. 84 bytes
Correct answer: B. 20 bytes
Correct answer: A. 76.19%
Correct answer: B. B and C Only
Correct answer: A. A, C, D, B
Correct answer: A. I and II only
Directions (Q36–40): A 3000 km long trunk operates at 1.536 Mbps and is used to transmit 64-byte frames using a sliding window protocol. The propagation delay is 6 μs/km.
Correct answer: A. Tt = 333.33 μs, Tp = 18000 μs
Correct answer: C. 0.901
Correct answer: A. Unicast address
Directions (Q96–100): An IP datagram arrives with the following partial header (hexadecimal): 45 00 00 54 00 03 00 00 20 06 …
What is the size of datagram?
Bytes 3–4 give the total length: 0x0054 = 84 bytes.
The Solution to Silly Window Syndrome problem is/are:
I. Nagle's Algorithm Q
II. Clark's Algorithm
III. Jacobson's Algorithm
IV. Piggy backing Algorithm
Nagle's algorithm fixes the sender side (send small data only when ACKs return) and Clark's solution fixes the receiver side (advertise a zero window until a reasonable amount is free).
Which of the statements given below is/are correct? It is always important and useful to include an 'alt' attribute on 'img' tag in HTML because
A. users who cannot see the image due to vision impairment can have a textual description of the image (which can be spoken aloud by a screen reader).
B. If the image fails to load (slow connection, broken path, etc.) then alt text is displayed instead.
C. SEO (Search Engine Optimization) benefits.
Choose the correct answer from the options given below:
Correct answer: D. A, B, and C f()
Alt text is read aloud by screen readers, is shown when the image fails to load, and helps search engines understand the image. All three are reasons.
Consider a code with only four valid code words: 0000000000,0000011111,1111100000, and 1111111111. This code has distance 5. If the code word arrived is 0000000111 then the original code word must be _____
Correct answer: A. 0000011111
0000000111 differs from 0000000000 in 3 bits and from 0000011111 in 2 bits, so it decodes to 0000011111.
Which tag is used to enclose any number of javascript statements in HTML document?
Correct answer: B. <script>
JavaScript statements are enclosed in <script> … </script>.
The full form of ICANN is
Correct answer: A. Internet Corporation for Assigned Names and Numbers
ICANN is the Internet Corporation for Assigned Names and Numbers.
Match List I with List II. List I: (a) Frame attribute, (b) <tr> tag, (c) Valign attribute, (d) <a> tag. List II: (i) To create a link in HTML, (ii) For vertical alignment of content in a cell, (iii) To enclose each row in a table, (iv) To specify the side of the table frame that displays a border.
Correct answer: C. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
frame sets which sides show a border; <tr> encloses a row; valign aligns cell content vertically; <a> makes a link.
Everyone in a group of N people wants to communicate secretly with the N − 1 others using a symmetric key system, with no pair's traffic decodable by the others. The number of keys required in the system as a whole is
Correct answer: B. N(N − 1)/2
Each pair needs its own shared key: C(N, 2) = N(N − 1)/2.
