Recent questions and answers in Computer Networks - GATE Overflow

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1

Stanford course
If a voice call has missing data it makes it hard to understand the speaker. Therefore, we commonly allow time for a limited number of retransmissions before playing the sound to the listener. If the network path (in each direction) has total packetization delay ... and 10ms, how large (in milliseconds) does the playback buffer need to be if we want to allow for one retransmission?

answered 14 hours ago in Computer Networks by hxt365 (11 points) | 189 views

+17 votes

5 answers

2

GATE2018-14
Consider the following statements regarding the slow start phase of the TCP congestion control algorithm. Note that cwnd stands for the TCP congestion window and MSS window denotes the Maximum Segments Size: The cwnd increases by $2$ MSS on every successful acknowledgment The cwnd approximately doubles ... are true Only $\text{(iv)}$ is true Only $\text{(i)}$ and $\text{(iv)}$ are true

answered 19 hours ago in Computer Networks by Harender Singh (59 points) | 4.9k views

+17 votes

4 answers

3

GATE2009-46
In the RSA public key cryptosystem, the private and public keys are $(e, n)$ and $(d, n)$ respectively, where $n=p \times q$ and $p$ and $q$ are large primes. Besides, $n$ is public and $p$ and $q$ are private. Let $M$ ... Which of the above equations correctly represents RSA cryptosystem? I and II I and III II and IV III and IV

answered 22 hours ago in Computer Networks by chirudeepnamini Active (2.3k points) | 2.3k views

+19 votes

7 answers

4

GATE2003-83
A $2$ $km$ long broadcast LAN has $10^7$ bps bandwidth and uses CSMA/CD. The signal travels along the wire at $2 \times 10^8$ m/s. What is the minimum packet size that can be used on this network? $50$ $\text{bytes}$ $100$ $\text{bytes}$ $200$ $\text{bytes}$ None of the above

answered 1 day ago in Computer Networks by shivam panchbhai (11 points) | 3.2k views

+44 votes

8 answers

5

GATE2015-2-52
$\text{Host A}$ sends a $\text{UDP}$ datagram containing $8880\text{ bytes}$ of user data to $\text{host B}$ over an $\text{Ethernet LAN}.$ Ethernet frames may carry data up to $1500\text{ bytes (i.e. MTU = 1500 bytes)}.$ Size of $\text{UDP}$ ... what will be the contents of offset field in the last fragment? $6$ and $925$ $6$ and $7400$ $7$ and $1110$ $7$ and $8880$

answered 1 day ago in Computer Networks by chirudeepnamini Active (2.3k points) | 7.6k views

+1 vote

3 answers

6

If m number of bits are used for representing a sequence number in selective-repeat ARQ

answered 3 days ago in Computer Networks by rituraj2847 (11 points) | 2.7k views

0 votes

5 answers

7

UGCNET-June2014-II-01
Infrared signals can be used for short range communication in a closed area using _______ propagation. Ground Sky Line of sight Space

answered 3 days ago in Computer Networks by 82sindhu (11 points) | 2.3k views

+1 vote

1 answer

8

computer networks general
Which book is good for numerical problems for computer networks for GATE?

answered 4 days ago in Computer Networks by `JEET Boss (11.2k points) | 72 views

+1 vote

2 answers

9

Kurose and Ross Edition 6 Exercise 1 Question R24 (Page No 70)
What is an application-layer message? A transport-layer segment? A network-layer datagram? A link-layer frame?

answered 6 days ago in Computer Networks by koushriek (11 points) | 72 views

+46 votes

7 answers

10

GATE2005-74
Suppose the round trip propagation delay for a $10\text{ Mbps}$ Ethernet having $48\text{-bit}$ jamming signal is $46.4\ \mu s$. The minimum frame size is: $94$ $416$ $464$ $512$

answered Nov 8 in Computer Networks by Chirag Shilwant (81 points) | 10.3k views

+13 votes

4 answers

11

GATE2015-2-41
Consider the following routing table at an IP router: $\begin{array}{|l|l|l|} \hline \textbf {Network No} & \textbf {Net Mask} & \textbf{Next Hop} \\\hline \text {128.96.170.0} & \text{255.255.254.0} & \text{Interface $ ... a, ii-c, iii-e, iv-d i-a, ii-d, iii-b, iv-e i-b, ii-c, iii-d, iv-e i-b, ii-c, iii-e, iv-d

answered Nov 7 in Computer Networks by prithatiti (149 points) | 3.4k views

+2 votes

1 answer

12

Data communication and networking by forouzan 12.7 Exercise Qn 16
16. In a CDMA/CD network with a data rate of 10 Mbps, the maximum distance between any station pair is found to be 2500 m for the correct operation of the collision detection process. What should be the maximum distance if we increase the data rate to 100 Mbps? To 1 Gbps? To 10 Gbps?

answered Nov 7 in Computer Networks by Mk Utkarsh Boss (35.4k points) | 47 views

0 votes

1 answer

13

Data communication and networking by forouzan 12.7 Exercise Qn 15
15. In a CDMA/CD network with a data rate of 10 Mbps, the minimum frame size is found to be 512 bits for the correct operation of the collision detection process. What should be the minimum frame size if we increase the data rate to 100 Mbps? To 1 Gbps? To 10 Gbps?

answered Nov 7 in Computer Networks by Mk Utkarsh Boss (35.4k points) | 18 views

0 votes

0 answers

14

Data communication and networking by forouzan 12.7 Exercise
11. We have a pure ALOHA network with 100 stations. If $T_{fr} = 1 \mu s$, what is the number of frames each station can send to achieve the maximum efficiency. 12. Repeat Exercise 11 for slotted ALOHA.

asked Nov 7 in Computer Networks by Mk Utkarsh Boss (35.4k points) | 22 views

+12 votes

4 answers

15

GATE2004-IT-26
A subnet has been assigned a subnet mask of $255.255.255.192$. What is the maximum number of hosts that can belong to this subnet? $14$ $30$ $62$ $126$

answered Nov 7 in Computer Networks by prithatiti (149 points) | 1.7k views

+1 vote

2 answers

16

UGCNET-june2009-ii-48
After sending a message, the sender should not be able to, at a later date, deny having sent the message, is referred to as: (A) Authenticity (B) Non-Repudiability (C) Auditability (D) Repudiability

answered Nov 6 in Computer Networks by Shailendra_ (381 points) | 218 views

+19 votes

3 answers

17

GATE2008-IT-70
The total number of keys required for a set of $n$ individuals to be able to communicate with each other using secret key and public key cryptosystems, respectively are: $n(n-1)$ and $2n$ $2n$ and $\dfrac{n(n - 1)}{2}$ $\dfrac{n(n - 1)}{2}$ and $2n$ $\dfrac{n(n - 1)}{2}$ and $n$

answered Nov 6 in Computer Networks by Shailendra_ (381 points) | 2.6k views

0 votes

1 answer

18

Reading Doubt
Which has lower latency amongst “Switch” and “Router”. And why ?

answered Nov 6 in Computer Networks by Sampratick 12 (19 points) | 46 views

+3 votes

1 answer

19

cn mac
A 8-node network runs the carrier sense Multiple Access (CSMA) MAC protocol. The maximum data rate of the network is 10 Megabits/s. Including retries, each node sends traffic according to some unknown random process at an average rate of 1 Megabit/s ... packets. What fraction of packets sent by the nodes (including retries) experience a collision?_________% (correct to two decimal places).

answered Nov 3 in Computer Networks by rahul_vicky (51 points) | 144 views

+5 votes

4 answers

20

tanenbaum computer networks
A $3000$km-long T1 trunk having Transmission time $1.544$ Mbps is used to transmit $64$byte frames using Go back -N. If the propagation speed is $6$ μsec/km, how many bits should the sequence numbers be?

answered Nov 3 in Computer Networks by rahul_vicky (51 points) | 1.9k views

0 votes

4 answers

21

TCP-congestion control
Assume a scenario where the size of congestion window of a TCP connection be 40 KB when a timeout occurs. The maximum segment size (MSS) be 2 KB. Let the propagation delay be 200 msec. The time taken by the TCP connection to get back to 40 ... is 6000msec.I am taking MSS as 2KB.ls someone explain NOTE:same question also asked here https://gateoverflow.in/1794/gate2014-1-27

answered Nov 3 in Computer Networks by rahul_vicky (51 points) | 502 views

0 votes

1 answer

22

Andrew S. Tanenbaum Edition 5th Exercise 6 Question 30 (Page No. 609)
Consider the effect of using slow start on a line with a 10-msec round-trip time and no congestion. The receive window is 24 KB and the maximum segment size is 2 KB. How long does it take before the first full window can be sent?

answered Nov 3 in Computer Networks by raju paul (337 points) | 36 views

+3 votes

2 answers

23

Fragmentation
A TCP message consisting of 2800 bytes is passed to IP for delivery across two networks. The first network can carry a maximum payload of 1500 bytes per frame and the second network can carry a maximum payload of 500 bytes per frame, excluding network overhead. ... IP overhead in the second network for this transmission? Doubt:- Answer is given as 120 Bytes but I am getting 140 Bytes

answered Nov 2 in Computer Networks by raju paul (337 points) | 373 views

0 votes

1 answer

24

ME adv Test
Suppose that host A is connected to a router R1, R1 is connected to another router R2 and R2 is connected to host B. Suppose that a TCP message that contains 900 bytes of data and 20 bytes of TCP header is passed to the IP layer at host A for delivery to B. Assume ... Offset=63 LENGTH=460; DF=0;MF=0;Offset=60. (Given ans is C can anyone help with this question whether ans is D or C? )

answered Nov 2 in Computer Networks by raju paul (337 points) | 61 views

+1 vote

2 answers

25

UGCNET-July-2018-II-41
A slotted ALOHA network transmits 200-bit frames using a shared channel with a 200 Kbps bandwidth. Find the throughput of the system (all stations put together) produces 250 frames per second: 49 368 149 151

answered Nov 1 in Computer Networks by abhinav kumar (75 points) | 1.2k views

0 votes

2 answers

26

Ace test series
Guys, I am not getting C as the ans..Can someone help.

answered Oct 29 in Computer Networks by kd..... Junior (837 points) | 87 views

+1 vote

1 answer

27

forouzan crc generator
find the status of the following generators related to two isolated, single bit errors. a.) x+1 b,) x^4+1 c) x^7+x^6+1 d) x^15+x^14+1 please explain this with examples in detail

answered Oct 29 in Computer Networks by kd..... Junior (837 points) | 141 views

+3 votes

5 answers

28

GATE2019-49
Consider that $15$ machines need to be connected in a LAN using $8$-port Ethernet switches. Assume that these switches do not have any separate uplink ports. The minimum number of switches needed is ______

answered Oct 24 in Computer Networks by Satbir Boss (20.6k points) | 2.7k views

0 votes

1 answer

29

UDP Socket
Why UDP cannot communicate with multiple peers simultaneously, while it can connect twice to an already connected UDP socket?

answered Oct 23 in Computer Networks by Himanshu Kashyap Junior (539 points) | 46 views

+60 votes

15 answers

30

GATE2009-57, ISRO2016-75
Frames of $\text{1000 bits}$ are sent over a $10^6$ $\text{bps}$ duplex link between two hosts. The propagation time is $\text{25 ms}$. Frames are to be transmitted into this link to maximally pack them in transit (within the link). What is the minimum ... distinctly? Assume that no time gap needs to be given between transmission of two frames. $I=2$ $I=3$ $I=4$ $I=5$

answered Oct 22 in Computer Networks by Manik Shekhar (11 points) | 15.1k views

0 votes

1 answer

31

Andrew S. Tanenbaum Edition 5th Exercise 6 Question 39 (Page No. 609)
To get around the problem of sequence numbers wrapping around while old packets still exist, one could use 64-bit sequence numbers. However, theoretically, an optical fiber can run at 75 Tbps. What maximum packet lifetime is ... even with 64-bit sequence numbers? Assume that each byte has its own sequence number, as TCP does.

answered Oct 22 in Computer Networks by s_dr_13 (167 points) | 30 views

0 votes

1 answer

32

Andrew S. Tanenbaum Edition 5th Exercise 8 Question 32 (Page No. 874)
The Diffie-Hellman key exchange is being used to establish a secret key between Alice and Bob. Alice sends Bob (227, 5, 82). Bob responds with (125). Alice’s secret number, x, is 12, and Bob’s secret number, y, is 3. Show how Alice and Bob compute the secret key.

answered Oct 21 in Computer Networks by aditi19 Active (5k points) | 43 views

0 votes

1 answer

33

Andrew S. Tanenbaum Edition 5th Exercise 8 Question 18 (Page No. 873)
Alice and Bob use RSA public key encryption in order to communicate between them. Trudy finds out that Alice and Bob shared one of the primes used to determine the number n of their public key pairs. In other words, Trudy found out that na = pa × q and nb = pb × q. How can Trudy use this information to break Alice’s code?

answered Oct 21 in Computer Networks by aditi19 Active (5k points) | 30 views

+1 vote

2 answers

34

Andrew S. Tanenbaum Edition 5th Exercise 8 Question 17 (Page No. 873)
Using the RSA public key cryptosystem, with a = 1, b = 2 . . . y = 25, z = 26. (a) If p = 5 and q = 13, list five legal values for d. (b) If p = 5, q = 31, and d = 37, find e. (c) Using p = 3, q = 11, and d = 9, find e and encrypt ‘‘hello’’.

answered Oct 21 in Computer Networks by aditi19 Active (5k points) | 62 views

0 votes

1 answer

35

Kurose and Ross Edition 6 Exercise 1 Question R16 (Page No 69)
Consider sending a packet from a source host to a destination host over a fixed route. List the delay components in the end-to-end delay. Which of these delays are constant and which are variable?

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 16 views

0 votes

1 answer

36

Kurose and Ross Edition 6 Exercise 1 Question R21 (Page No 70)
Visit the Queuing and Loss applet at the companion Web site. What is the maximum emission rate and the minimum transmission rate? With those rates, what is the traffic intensity? Run the applet with these rates and determine how ... determine again how long it takes for packet loss to occur. Are the values different? Why or why not?

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 20 views

0 votes

1 answer

37

Kurose and Ross Edition 6 Exercise 1 Question R19 (Page No 69)
Suppose Host A wants to send a large file to Host B. The path from Host A to Host B has three links, of rates R1 = 500 kbps, R2 = 2 Mbps, and R3 = 1 Mbps. Assuming no other traffic in the network, what is the throughput for ... long will it take to transfer the file to Host B? Repeat (a) and (b), but now with R2 reduced to 100 kbps.

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 16 views

0 votes

1 answer

38

Kurose and Ross Edition 6 Exercise 1 Question R18 (Page No 69)
How long does it take a packet of length 1,000 bytes to propagate over a link of distance 2,500 km, propagation speed 2.5 · 108 m/s, and transmission rate 2 Mbps? More generally, how long does it take a packet ... s, and transmission rate R bps? Does this delay depend on packet length? Does this delay depend on the transmission rate?

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 16 views

0 votes

1 answer

39

Kurose and Ross Edition 6 Exercise 2 Question R16 (Page No 170)
Suppose Alice, with a Web-based e-mail account (such as Hotmail or Gmail), sends a message to Bob, who accesses his mail from his mail server using POP3. Discuss how the message gets from Alice’s host to Bob’s host. Be sure to list the series of application-layer protocols that are used to move the message between the two hosts.

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 27 views

0 votes

1 answer

40

Andrew S. Tanenbaum Edition 5th Exercise 6 Question 2 (Page No. 606)
Primitives of transport service assume asymmetry between the two end points during connection establishment, one end (server) executes LISTEN while the other end (client) executes CONNECT. However, in peer to peer ... client functionality. How can transport service primitives may be used to build such peer to peer applications?

answered Oct 21 in Computer Networks by `JEET Boss (11.2k points) | 14 views

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