Computer Knowledge

Computer Networks

2,614 Questions

Computer networks involve the architecture, protocols, and security measures used for digital communication. This collection covers OSI model layers, IP addressing, data transmission, and cryptographic standards. These concepts are vital for the computer knowledge sections of banking and government exams.

OSI model layersNetwork protocolsIP subnet maskingData encryption standardsServer configurationsNetwork commands

Computer Networks Questions

Multiple choice

Frames of 1000 bits are sent over a 106 bps duplex link between two hosts. The propagation time is 25 ms. Frames are to be transmitted into this link to maximally pack them in transit (within the link).

Suppose that the sliding window protocol is used with the sender window size of 2l, where l is the number of bits identified in the earlier part and acknowledgements are always piggy backed. After sending 2l frames, what is the minimum time the sender will have to wait before starting transmission of the next frame? (Identify the closest choice ignoring the frame processing time.)

  1. 16 ms

  2. 18 ms

  3. 20 ms

  4. 22 ms
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple choice

Which of the following is NOT true with respective to a transparent bridge and a router?

  1. Both bridge and router selectively farward data packets

  2. A bridge uses IP addresses while a router uses MAC addresses

  3. A bridge builds up its routing table by inspecting incoming packets

  4. A router can connect between a LAN and a WAN.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bridge is the device which work at data link layer whereas router works at network layer. Both selectively forward packets, build routing table & connect between LAN & WAN but since bridge works at data link it uses MAC addresses to route whereas router uses IP addresses.

Multiple choice

The address resolution protoc0l (ARP) is used for

  1. Finding the IP address from the DNS

  2. Finding the IP address of the default gateway

  3. Finding the IP address that corresponds to a MAC address

  4. Finding the MAC address that corresponds to an IP address
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Address resolution protocol is applied to determine MAC address corresponding to an IP address.

Multiple choice

Consider three IP networks A, B and C. Host HA in network A send messages each containing 180 bytes of application data to a host HC in network C. The TCP layer prefixes a 20 byte header to the message. This passes through an intermediate network B. The maximum packet size, including 20 byte IP header, in each network is A :1000 bytes B :100 bytes C :1000 bytes The network A and B are connected through a 1 Mbps link, while B and C are connected by a 512 Kbps link (bps=bits per second).

What is the rate at which application data is transferred to host Hc? Ignore errors, acknowledgements, and other overheads.

  1. 325.5 Kbps

  2. 354.5 Kbps

  3. 409.6 Kbps

  4. 512.0 Kpps
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple choice

Consider three IP networks A, B and C. Host HA in network A send messages each containing 180 bytes of application data to a host HC in network C. The TCP layer prefixes a 20 byte header to the message. This passes through an intermediate network B. The maximum packet size, including 20 byte IP header, in each network is A :1000 bytes B :100 bytes C :1000 bytes The network A and B are connected through a 1 Mbps link, while B and C are connected by a 512 Kbps link (bps=bits per second).

Assuming that the packets are correctly delivered, how many bytes, including headers, are delivered to the IP layer at the destination for one application message, in the best case ? Consider only data packets.

  1. 200

  2. 220

  3. 240

  4. 260
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

At A Data + Header = 200 bytes. This would require only 1 packet of N/W A At B 200 bytes of payload from network A is packed in 80 payload + 20 header packet. This would require 20+80 20 + 80 20+40 Packets total 260 bytes. These are transferred to C

Multiple choice

What is the mechanism by which a computer obtains an internet address?

  1. Reverse Address Resolution protocol (RARP)

  2. Address Resolution Protocol (ARP)

  3. Dynamic host configuration protocol (DHCP)

  4. Internet protocol (IP)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

RARP is the protocol, which is used to obtain the internet address for a computer, whereas ARP is used in a LAN to determine a destination computer's hardware address.

Multiple choice

What is the base of the WWW?

  1. Client-server

  2. Local-server

  3. 3-tier

  4. 4 - tier
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The World Wide Web architecture follows a client-server model where web browsers (clients) request resources from web servers (servers) using HTTP protocol.

Multiple choice

What is the server port?

  1. It is the domain name or IP address of the computer, running web server software.

  2. It gives the port number, on which web server is waiting for requests.

  3. It gives version and name of the protocol web server is using.

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The server port number specifies which communication endpoint the web server is listening on. Common ports are 80 for HTTP and 443 for HTTPS. The domain name/IP identifies the computer, while the port identifies the specific service/process on that computer.

Multiple choice

Which of the following protocols is a stateless protocol?

  1. TELNET

  2. FTP

  3. TCP

  4. HTTP

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In networks, stateless protocol treats each request and response as an independent event. HTTP is used to communicate between client and server, where each request and response is treated as an independent event. Hence, it is stateless.

Multiple choice

By default, what is the port number used by http?

  1. 80

  2. 443

  3. 81

  4. 440

  5. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Port number 80 is the default port used by http. Port numbers are generally used identify senders and receivers of messages.

This option is correct.

Multiple choice

What is the total number of possible IPv4 IP addresses?

  1. 256

  2. 1,024

  3. 4,294,967,296

  4. 4,096

  5. 65,536
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

IPv4 defines IP addresses in a 32-bit format, which looks like 123.123.123.123. Each three-digit section can include a number from 0 to 255, which means the total number of IPv4 addresses available is 4,294,967,296 (256 x 256 x 256 x 256 or 2^32).