L1. Why do we need protocol layering?

Question 1

What is protocol layering?

Answer 1

The organization of network communication protocols into a hierarchical structure

Question 2

What does a layer do?

Answer 2

Each layer is responsible for specific tasks related to data transmission

Question 3

How do different layers interact?

Answer 3

Adjacent layers interact with eachother through standardized interfaces

Question 4

What are the benefits of protocol layering?

Answer 4

Protocol layering allows for abstraction, modularization, and easier maintenance of networking systems

Question 5

What does abstraction mean?

Answer 5

Abstraction involves hiding complex implementation details behind simpler interfaces

Question 6

What does abstraction mean in the context of protocol layering?

Answer 6

Each layer in the protocol stack performs specific tasks without requiring any information about the implementation of protocols at other layers

Question 7

What are the benefits of abstraction in the context of protocol layering?

Answer 7

Abstraction facilitates design, implementation, and troubleshooting of network protocols by allowing developers to focus on one layer at a time

Question 8

Do changes to one network layer affect other layers?

Answer 8

Since each layer operates independently, changes or updates to one layer does not affect other layers so long as the interfaces between layers remain consistent

Question 9

What model of the network stack have we looked at in this course?

Answer 9

The five-layer TCP/IP model

Question 10

Name the layers of the protocol stack

Answer 10

Application Layer, Transport Layer, Network Layer, Link Layer, Physical Layer

Question 11

What does the application layer do?

Answer 11

The application layer defines protocols and standards for application-level services

Question 12

What are some application-level services?

Answer 12

Web browsing, email, file transfer, remote access

Question 13

Name some application layer protocols and what they are used for

Answer 13

HTTP for web browsing, SMTP, IMAP, and POP3 for email, FTP for file transfer, DNS for resolving domain names to IP addresses

Question 14

How do the application layer and transport layer communicate?

Answer 14

The application layer provides data to the transport layer, along with information on how the data should be transmitted, such as specifications for which transport protocol to be used. The transport layer takes outgoing data provided by the application layer and segments it, and makes sure incoming data is delivered to the correct process on the host

Question 15

What does the transport layer do?

Answer 15

The transport layer is responsible for creating end-to-end connections between hosts

Question 16

Name some transport layer protocols

Answer 16

The two main transport layer protocols are TCP and UDP. TCP is a connection-oriented protocol that ensures reliable, ordered delivery of data packets with mechanisms for error detection , retransmission, and flow control. UDP is connectionless and does not provide any of the reliability of TCP, but has lower latency. There is also the QUIC protocol which is based on UDP and offers similar low latency but has added features for reliability and security

Question 17

What does the network layer do?

Answer 17

The network layer is responsible for addressing, routing, and forwarding data between networks. It determines the best path for data transmission accross interconnected networks.

Question 18

Name some network layer protocols

Answer 18

The primary protocol used in the network layer is the Internet Protocol (IP), which includes version IPv4 and IPv6

Question 19

What does the link layer do?

Answer 19

The link layer is responsible for the transmission of data between adjacent nodes in a network. It divides data into frames, adding headers and trailers for error detection and correction. It provides MAC addresses to network interfaces. It performs access control to avoid collisions in shared media networks. It detects and corrects errors that occur during transmission using techniques like CRC

Question 20

Name some link layer protocols

Answer 20

Link layer protocols include Ethernet, for local area networks, and Wi-Fi for wireless local area networks

Question 21

What does the physical layer do?

Answer 21

The physical layer is responsible for transmitting raw data bits over physical media, such as copper wire, fibre optics, or wireless transmission. It defines the electrical, optical, or radiosignalling characteristics used for the physical transmission of data

Question 22

Name some physical layer protocols

Answer 22

The physical layer doesn’t have protocols as such, but it has standards and specifications. Link layer protocols Ethernet and Wi-Fi also encompass specifications used at the physical layer