Computer Networking Quiz (or) Computer Networking MCQ (Multiple Choice Questions)

1 .

To prevent Service Advertisements (SAPs) from flooding a network, Cisco routers do not forward them. How are services advertised to other networks?

A)

Cisco routers filter out all SAPs

B)

SAPs aren’t necessary with Cisco routers

C)

Each router assigns a service number and broadcasts that

D)

Each router builds its own SAP table and forwards that every 60 seconds

Correct Answer : Option (D) : Each router builds its own SAP table and forwards that every 60 seconds

Explanation : Cisco routers build SAP tables and forward the table every 60 seconds. All SAPs can’t befiltered even with 4.x since NDS and time synchronization uses SAPs.

2 .

Which routing protocol has a maximum network diameter (hop count) of 15?

A)

RIPv1

B)

RIPv2

C)

Both RIPv1 and RIPv2

D)

EIGRP

Correct Answer : Option (C) : Both RIPv1 and RIPv2

Explanation : Both RIPv1 and RIPv2 support a maximum hop count of 15 because they use 4-bits to store this value. RIPv1 uses classful routing whereas RIPv2 uses classless routing. The routing updates are broadcasted over the network. It notifies routers about the update so that they update their own routing tables.

3 .

How often does a RIPv1 router broadcast its routing table by default?

A)

Every 90 seconds

B)

Every 30 seconds

C)

Every 60 seconds

D)

RIPv1 does not broadcast periodically

Correct Answer : Option (B) : Every 30 seconds

Explanation : RIPv1 router broadcasts its routing table every 30 seconds by default. The broadcasted routing table can be used by other routers to find the shortest path among the network devices.

4 .

Which command displays RIP routing updates?

A)

Debug IP RIP

B)

Show IP Route

C)

Show Protocols

D)

Debug IP Route

Correct Answer : Option (A) : Debug IP RIP

Explanation : The debug IP rip command is used to show the Internet Protocol (IP) Routing Information Protocol (RIP) updates being sent and received on the router. It verifies that the updates are being broadcasted and not multicasted.

5 .

Where should we use default routing?

A)

On stub networks- which have only one exit path out of the network

B)

Minimum five exit paths out of the network

C)

Maximum five exit paths out of the network

D)

Which have more than one exit path out of the network

Correct Answer : Option (A) : On stub networks- which have only one exit path out of the network

Explanation : RIP gives a full route table update every 30 seconds. The broadcasted routing table can be used by other routers to find the shortest path among the network devices.

6 .

In cryptography, what is cipher?

A)

encrypted message

B)

decrypted message

C)

algorithm for performing encryption and decryption

D)

both algorithm for performing encryption and decryption and encrypted message

Correct Answer : Option (C) : algorithm for performing encryption and decryption

Explanation : Cipher is a method to implement encryption and decryption of messages travelling in a network. It’s used to increase the confidentiality of the messages.

7 .

Which one of the following algorithm is not used in asymmetric-key cryptography?

A)

rsa algorithm

B)

dsa algorithm

C)

diffie-hellman algorithm

D)

electronic code book algorithm

Correct Answer : Option (D) : electronic code book algorithm

Explanation : Electronic code book algorithm is a block cipher method in which each block of text in an encrypted message corresponds to a block of data. It is not feasible for block sizes smaller than 40 bits.

8 .

What is data encryption standard (DES)?

A)

bit cipher

B)

block cipher

C)

byte cipher

D)

stream cipher

Correct Answer : Option (B) : block cipher

Explanation : DES is a symmetric key block cipher in which the block size is 64 bits and the key size is 64 bits. It is vulnerable to some attacks and is hence not that popularly used.

9 .

Which one of the following is a cryptographic protocol used to secure HTTP connection?

A)

Resource Reservation Protocol(RRP)

B)

Transport Layer Security (TLS)

C)

Explicit Congestion Notification (ECN)

D)

Stream Control Transmission Protocol (SCTP)

Correct Answer : Option (B) : Transport Layer Security (TLS)

Explanation : TLS has strong message authentication and key-material generation to prevent eavesdropping, tampering and message forgery. It has been used since the year 1996.

10 .

Cryptographic hash function takes an arbitrary block of data and returns _________

A)

fixed size bit string

B)

variable size bit string

C)

variable sized byte string

D)

both fixed size bit string and variable size bit string

Correct Answer : Option (A) : fixed size bit string

Explanation : Cryptographic hash functions are used in digital signatures and message authentication codes. The only issue with it is that it returns the same hash value every time for a message making it vulnerable to attackers to evaluate and break the cipher.