# Recent questions tagged computer-networks

1 vote
1
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 _______ $0000011111$ $0000000000$ $1111100000$ $1111111111$
2
Using ‘RSA’ public key cryptosystem, if $p=3$, $q=11$ and $d=7$, find the value of $e$ and encrypt the number $’19’$ $20, 19$ $33,11$ $3, 28$ $77, 28$
3
Protocols in which the sender sends one frame and then waits for an acknowledgment before proceeding for next frame are called as ______ Simplex protocols Unrestricted simplex protocols Simplex stop and wait protocols Restricted simplex protocols
4
Which among the following statement(s) is(are) true? A hash function takes a message of arbitrary length and generates a fixed length code A hash function takes a message of fixed length and generates a code of variable length A hash function may give same hash value for distinct messages Choose the correct ... options given below: $(a)$ only $(b)$ and $(c)$ only $(a)$ and $(c)$ only $(b)$ only
5
Post office protocol (POP) is a message access protocol which is used to extract message for client. In this regards, which of the following are true? POP has two modes, Delete mode and keep In Delete mode, mail is deleted from mail box after each retrival In Delete mode, mail is deleted from mail box before each ... $(e)$ only $(a)$, $(b)$, $(c)$ and $(d)$ only $(a)$, $(b)$ and $(e)$ only
6
Match $\text{List I}$ with $\text{List II}$ ... $A-III, B-IV, C-II, D-I$ $A-II, B-III, C-IV, D-I$ $A-III, B-I, C-IV, D-II$
7
Given below are two statements: Statement $I$: The laws of nature put two fundamental limits on data rate of a channel. The H.Nyquist limit restricts the number of independent samples per second to twice the band-width in a Noiseless channel Statement $II$: Shannon's major ... $II$ are false Statement $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
8
Given below are two statements: Statement $I$: In Ceasar Cipher each letter of Plain text is replaced by another letter for encryption Statement $II$: Diffie-Hellman algorithm is used for exchange of secret key In the light of the above statements, choose the correct answer ... $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
9
Start and stop bits are used in serial communication for error detection error correction synchronization slowing down the communication
10
Repeaters function in Physical layer Data link layer Network layer Both (A) and (B)
11
What are the primary characteristics that distinguish a cell from a packet? cells are generally smaller that packets cells do not incorporate physical address all cells have the same fixed length packet cannot be switched
12
In networking terminology UTP means Unshielded Twisted pair Ubiquitious Teflon port Uniformly Terminating port Unshielded T- connector port
1 vote
13
How many bits are required to encode all twenty six letters, ten symbols, and ten numerals? $5$ $6$ $7$ $46$
14
Bit stuffing refers to Inserting a $’0’$ in user data stream to differentiate it with a flag Inserting a $’0’$ in flag stream to avoid ambiguity Appending a nibble to the flag sequence Appending a nibble to the user data stream
15
The address of a class $B$ Host is to be split into subnets with a $3$-bit subnet number. What is the maximum number of subnets and maximum number of hosts in each subnet? $8$ subnets and $262142$ hosts $6$ subnets and $262142$ hosts $6$ subnets and $1022$ hosts $8$ subnets and $1024$ hosts
16
The maximum data rate of a channel of $3000$-Hz bandwidth and SNR of $30$ db is $60000$ $15000$ $30000$ $3000$
17
Which of the following is minimum error code? Octal Code Binary Code Gray Code Excess-$3$ Code
1 vote
18
If the original size of data is $40$ then after adding error detection redundancy bit the size of data length is $26$ $36$ $46$ $56$
19
Which of the following would not be specified in a communication protocol? Header contents Trailer contents Error Checking Data content of message
Bit stuffing refers to Inserting a $’0’$ in user data stream to differentiate it with a flag Inserting a $’0’$ in flag stream to avoid ambiguity Appending a nibble to the flag sequence Appending a nibble to the user data stream
If the channel is band limited to $6\;kHz$ and signal to noise ratio is $16,$ what would be the capacity of channel? $16.15$ kbps $23.24$ kbps $40.12$ kbps $24.74$ kbps