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

1 .

The process of error checking and dropping of the header, delivering messages to appropriate process based on port number is called as _______

A)

Multiplexing

B)

Error correction

C)

Delivery of packets

D)

Demultiplexing

Correct Answer : Option (D) : Demultiplexing

Explanation : Demultiplexing is the process of error checking and dropping of the header, delivering messages to appropriate process based on port number. The transport layer does this on the receiver’s end after the packet is received and takes help of the header attached by the sender’s side transport layer during multiplexing.

2 .

Header size of the ICMP message is _____

A)

8-bytes

B)

8-bits

C)

16-bytes

D)

16-bits

Correct Answer : Option (A) : 8-bytes

Explanation : An ICMP message has an 8-byte header and a variable size data section. Out of the 8 bytes, the first 4 bytes are of a fixed format having the type, code and checksum fields and the next 4 bytes depend upon the type of the message.

3 .

The source-quench message in ICMP was designed to add a kind of ____________ to the IP.

A)

flow control

B)

router control

C)

switch control

D)

error control

Correct Answer : Option (A) : flow control

Explanation : Firstly, it informs the source that the datagram has been discarded. Secondly, it warns the source that there is congestion in the network. It’s type 4 error reporting message after which the source is expected to reduce the flow of packets.

4 .

During debugging, we can use the ____________ program to find if a host is alive and responding.

A)

java

B)

ping

C)

shell

D)

traceroute

Correct Answer : Option (B) : ping

Explanation : Ping program is used to find if a host is alive and responding. It is to be entered into a command line with the syntax “ping (IP address)” to be executed. Traceroute is a program used to find the shortest route to the destination IP.

5 .

Which of the following is the broadcast address for a Class B network ID using the default subnetmask?

A)

172.16.10.255

B)

172.255.255.255

C)

172.16.255.255

D)

255.255.255.255

Correct Answer : Option (C) : 172.16.255.255

Explanation : In this case, the class B network ID is 172.16.0.0. We know that the default mask of a class B network is 255.255.0.0. If we OR any address in a network with the complement of the default mask (0.0.255.255), we get the broadcast address of the network. In this case, the result of OR would be 172.16.255.255.

6 .

You have an IP address of 172.16.13.5 with a 255.255.255.128 subnet mask. What is your class of address, subnet address, and broadcast address?

A)

Class A, Subnet 172.16.13.0, Broadcast address 172.16.13.127

B)

Class B, Subnet 172.16.13.0, Broadcast address 172.16.13.255

C)

Class B, Subnet 172.16.0.0, Broadcast address 172.16.255.255

D)

Class B, Subnet 172.16.13.0, Broadcast address 172.16.13.127

Correct Answer : Option (D) : Class B, Subnet 172.16.13.0, Broadcast address 172.16.13.127

Explanation : We know that the prefix 172 lies in class B (128 to 191) of IPv4 addresses. From the subnet mask, we get that the class is divided into 2 subnets: 172.16.13.0 to 172.16.13.127 and 172.16.13.128 to 172.16.13.255. The IP 172.16.13.5 lies in the first subnet. So the starting address 172.16.13.0 is the subnet address and last address 172.16.13.127 is the broadcast address.

7 .

If you wanted to have 12 subnets with a Class C network ID, which subnet mask would you use?

A)

255.255.255.240

B)

255.255.255.248

C)

255.255.255.252

D)

255.255.255.255

Correct Answer : Option (A) : 255.255.255.240

Explanation :

If you have eight networks and each requires 10 hosts, you would use the Class C mask of 255.255.255.240. Why? Because 240 in binary is 11110000, which means you have four subnet bits and four host bits. Using our math, we’d get the following:

24-2=14 subnets

24-2=14 hosts.

8 .

Which of the following are Gigabit Ethernets?

A)

1000 BASE-CX

B)

1000 BASE-LX

C)

1000 BASE-SX

D)

All of the above

Correct Answer : Option (D) : All of the above

Explanation : In computer networking, Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second (1,000,000,000 bits per second), as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks, as a result of being considerably faster.

9 .

_________ is another kind of fiber optic network with an active star for switching.

A)

SW/NET

B)

S/NET

C)

NET/SW

D)

FS/NET

Correct Answer : Option (B) : S/NET

Explanation : A 50-MBd active star fiber optical Local area network (LAN) and its optical combiner and mixing rod splitter are presented. The limited power budget and relatively large tapping losses of light wave technology, which limit the use of fiber optics in tapped bus LAN topologies, are examined and proven tolerable in optical star topologies.

10 .

What is the maximum number of IP addresses that can be assigned to hosts on a local subnet that uses the 255.255.255.224 subnet mask?

A)

16

B)

24

C)

30

D)

35

Correct Answer : Option (C) : 30

Explanation : A /27 (255.255.255.224) is 3 bits on and 5 bits off. This provides 8 subnets, each with 30 hosts. Does it matter if this mask is used with a Class A, B, or C network address? Not at all. The number of host bits would never change.