Network Layer MCQ Quiz - Objective Question with Answer for Network Layer - Download Free PDF

The correct answer is: 1) A modem provides internet access, while a NIC manages local area network (LAN) traffic.

Key Differences Between Modem and NIC:

The correct answer is Propagation delay.

Key Points

• In a network, various types of delays can affect the transmission of a packet. These include propagation delay, queuing delay, transmission delay, and processing delay.
• Propagation delay refers to the time it takes for a signal to travel from the sender to the receiver. It is a function of the distance between the two points and the speed of the signal in the medium. If P is the only packet being transmitted and there was no earlier transmission, the propagation delay could be zero if the distance is negligible or if the signal is already at the receiver.
• Queuing delay is the time a packet spends waiting in a queue before it can be transmitted. Since P is the only packet and there were no earlier transmissions, the queuing delay could be zero.
• Transmission delay is the time required to push all the packet's bits onto the link. This delay depends on the packet's length and the transmission rate of the link. Since P is being transmitted, the transmission delay cannot be zero.
• Processing delay is the time it takes for a router or switch to process the packet header and make a forwarding decision. This is typically non-zero as it involves computational steps.

Additional Information

• Propagation delay is determined by the physical medium (e.g., copper wire, fiber optic) and the speed of light or electrical signals in that medium.
• The propagation delay is usually calculated as the distance divided by the speed of the signal. For example, in fiber optics, the speed is approximately 2/3 the speed of light in a vacuum.
• In high-speed networks, propagation delay can become significant, especially over long distances like transcontinental or undersea cables.
• Understanding and minimizing delays is crucial for optimizing network performance and ensuring efficient data transmission.

Explanation:

Multiplexing of Channels

Definition: Multiplexing is a method used in telecommunications to combine multiple signals into one signal over a shared medium. The goal is to maximize the utilization of the medium and to efficiently manage the bandwidth. There are various types of multiplexing, including Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), and others, depending on how the signals are combined and transmitted.

Working Principle: When two or more channels are multiplexed, their individual data streams are combined into a single data stream that can be transmitted over a single communication link. This process involves the allocation of the link’s bandwidth to the different channels, either by dividing the time (in TDM) or the frequency (in FDM) among them.

Example: In this specific case, we have two channels with bit rates of 150 Mbps and 300 Mbps respectively. When these two channels are multiplexed, their combined bit rate will be the sum of their individual bit rates.

Calculation:

To determine the bit rate of the link after multiplexing these two channels, we simply add their individual bit rates:

Bit rate of Channel 1 = 150 Mbps

Bit rate of Channel 2 = 300 Mbps

Bit rate of the link after multiplexing = Bit rate of Channel 1 + Bit rate of Channel 2

Bit rate of the link after multiplexing = 150 Mbps + 300 Mbps = 450 Mbps

Correct Option Analysis:

The correct option is:

Option 3: 450 Mbps

This option correctly represents the total bit rate of the link after multiplexing the two channels. The combined bit rate is the sum of the individual bit rates of the channels being multiplexed, which in this case is 150 Mbps + 300 Mbps = 450 Mbps

The correct answer is contains a lot of processing units under the common control unit supervision.

Key Points

• SIMD (Single Instruction, Multiple Data) is a type of computer organization where:
  • A single control unit issues one instruction, and multiple processing units execute that instruction simultaneously on different pieces of data.
  • This is typically used in parallel processing systems, such as GPUs and vector processors, to achieve high performance in tasks like matrix operations or image processing.

The correct answer is Telnet.

Key Points

• Any application that empowers users to remotely access another computer(no matter how far away) is called remote access.
• Telnet is an application protocol that uses a virtual terminal connection to offer bidirectional interactive text-oriented communication over the Internet.
• Telnet facilitates remote login on a computer.
• It also facilitates terminal emulation purposes.
• Telnet was developed in 1969.
• Telnet allows users to execute various application programmes on a distant site and then transport the results back to their local computer.

Additional Information

• The Hypertext Transfer Protocol (HTTP) is the backbone of the internet's data transfer.
  • It is a stateless protocol.
• Real-Time Protocol (RTP) is a protocol designed to handle real-time traffic (like audio and video) of the Internet.
• File Transfer Protocol is a set of rules that govern how computers transfer files from one system to another over the internet

Given:

Message size = 2400 bits.

The header of the transport layer = 150 bits.

Segment size at transport layer = (Header + Message size) = 150 + 2400 = 2550 bits.

Maximum, transmission unit at destination network = 900 bits

 So, At a time, data supported by the destination network = 900 – 26 = 874 bits.

Hence, 2550 bits are divided into packets having a maximum of 874 bits. So:

But 874 is not divisible by 8,

So, 

Length of packet 1 = 872 bits.

Length of packet 2 = 872 bits.

Length of packet 3 = 806 bits.

Total  = 2550 bits.

Network layer packets are transmitted via two networks, each of which uses a 26-bit header. So, The number of bits, including headers delivered to the destination network is:

Packet 1 (Data + Header) size = 26 + 26 + 872 = 924 bits.

Packet 2 (Data + Header) size = 26 + 26 + 872 = 924 bits.

Packet 3 (Data + Header) size = 26 + 26 + 806 = 858 bits.

 Total = 2706 bits. 

The correct answer is Gateway.

Key Points

• A device used to connect two or more different networks is called Gateway.
  • ​It is a network node used in telecommunications that connects two networks with different transmission protocols together.
  • It serves as an entry and exit point for a network as all data must pass through or communicate with the gateway prior to being routed.
  • It is also called as ' Protocol Converter ' because it can convert the data packets as per the destination network protocol requirement.
• Switches
  • ​A network switch forwards data packets between devices.
  • Switches are networking devices operating at layer 2 or a data link layer of the OSI model.
  • Switches can be hardware devices that manage physical networks or software-based virtual devices.
• Repeater
  • ​It operates at physical layer of the OSI model.
  • It is a hardware device that regenerates an incoming signal from the sender before retransmitting it to the receiver.
• Hub
  • ​A network hub is a node that broadcasts data to every computer or Ethernet-based device connected to it.
  •  A hub has many ports in it. They are generally used to connect computers in a LAN.

Key Points

Network layer protocols are,

• IP(Internet Protocol​),
• ARP(Address Resolution Protocol),
• ICMP (Internet Control Message Protocol).

Hence the correct answer is IP.

Additional Information

• SMTP (Simple Mail Transfer Protocol) is an application layer protocol in OSI.
• HyperText Transfer Protocol (HTTP), is the Web's application-layer protocol,
• Transmission Control Protocol (TCP) In terms of the OSI model, TCP is a transport-layer protocol.

Key Points

 A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A router is a hardware device that is used to receive, analyze and forward the incoming packets to another network.

Hence the correct answer is a router.

Additional Information

• The modem is a device that enables a computer to send or receive data over telephone or cable lines.
• Repeaters are network devices operating at the physical layer of the OSI model that amplifies or regenerates an incoming signal before retransmitting it.

The correct answer is option 4 i.e 180 KWh

Concept :

Energy Consumed = Load (in KW) x Time taken by load (in Hr)

Calculation :

Motor loaded at 30 KW

Time taken = 6 Hr

Energy consumed = 30 x 6 KWh = 180 KWh

Explanation:

Transmission Delay: 

This is the time it takes for a router to transmit the entire packet onto the outbound link. It depends on the packet size and the transmission rate of the link.

Queuing Delay: 

This is the time a packet spends waiting in a queue at a router before it can be transmitted. The delay depends on the number of other packets waiting in the queue and the link bandwidth.

Processing Delay: 

This is the time it takes for a router to process the packet header and make a forwarding decision. It depends on the router's processing power and the complexity of the packet header.

Therefore, all three delays are present in packet switching.

• Ring
  • Ring topology is like a bus topology, but with connected ends.
  • The node that receives the message from the previous computer will retransmit to the next node.
  • The data flows in one direction, i.e., it is unidirectional.
  • The data flows in a single loop continuously known as an endless loop.
  • It has no terminated ends, i.e., each node is connected to another node and having no termination point.
  • The data in a ring topology flow in a clockwise direction.
  • The most common access method of the ring topology is token passing.

Answer: Option 3

Concept: 

The Routers only contains 3 layer that's the reason sometimes they also called as 3-layer switch.

The Router is a physical or virtual internetworking device that is designed to receive, analyze, and forward data packets between computer networks. A router examines a destination IP address of a given data packet, and it uses the headers and forwarding tables to decide the best way to transfer the packets.

Explanation: 

At Intermediate Router R the packet will not go beyond the network layer. Hence Network layer will only be visited once at both the routers.

But the Data link layer will be visited twice.

Hence Network layer will be visited 4 times and the Data link layer will be visited 6 times (1 + 2 (at R) + 2 (at R) + 1 = 6 )

The correct answer is: FTP

Concept:

FTP stands for File Transfer Protocol. It is a protocol that is part of the TCP/IP suite, specifically designed for transmitting files between computers on the Internet. FTP uses the client-server model where the client machine establishes the connection to a server to upload or download files. FTP uses two separate connections for command and data to ensure reliable and efficient file transfer, making it particularly useful for transferring large files or groups of files.

Here's brief information about the other options:

2) ASCII: The American Standard Code for Information Interchange is a character encoding standard. ASCII is used to represent text in computers and other devices that use text. It does not involve file transfer.

3) BCD: Binary Coded Decimal is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. It is a way to represent decimal numbers in binary format. It does not involve file transfer.

4) HTTP: The Hypertext Transfer Protocol is used for transmitting hypertext over the internet. Hypertext is the structured text that uses hyperlinks between nodes containing text. HTTP is the foundation of data communication on the World Wide Web but it's not specifically designed for file transfers - it's more broadly used to request and transmit web pages and other data from a server to a client (like a web browser). HTTP can be used to transfer files as part of this data exchange, but it is not specifically a file transfer protocol.