Networking

Question 1

Define the Application Layer.

Answer 1

Provides services directly to end users, is the user interface to the network. Protocols = HTTPS & DNS

Question 2

Define the Presentation Layer.

Answer 2

Translation of data between a networking service and an application; does:
- format conversion
- data compression
- encryption/decryption.

Question 3

Define the Data link Layer.

Answer 3

concerned with close devices, and uses ethernet protocols to organise bits for reliable delivery. Ethernet communication is mediated by L2 switches.

Question 4

Define the Physical Layer.

Answer 4

Transmission and reception of raw bit streams
over a physical medium. Converts data bits -> electrical signals and manages voltages + timing.

Question 5

Define the session layer.

Answer 5

manages the establishment, maintenance and termination of communication sessions. Also handles dialog control.

Question 6

Define the Transport Layer.

Answer 6

Ensures end to end communication between devices managing quality and reliability.
protocols: TCP, UDP and TLS (or ssl).

Question 7

Define the Network Layer.

Answer 7

responsible for logical addressing and routing of data packets. uses IP to decide the best path for data to travel. Routers operate at this level.

Question 8

What data unit is the application layer?

Answer 8

Data unit.

Question 9

What data unit is session layer?

Answer 9

data

Question 10

What data unit is network layer?

Answer 10

packets

Question 11

What data unit is the session layer?

Answer 11

data

Question 12

What data unit is the transport layer?

Answer 12

segments/ datagram

Question 13

What data unit is the presentation layer?

Answer 13

data

Question 14

What data unit is the data link layer?

Answer 14

frames

Question 15

What are the components of an ethernet data frame?

Answer 15

• destination mac addres
• source mac address
• Type
• Data
• CRC (cyclical redundancy check)

Question 16

what are the three types of addresses in networking?

Answer 16

domain name, mac address and IP address

Question 17

What does CRC do?

Answer 17

error detection

Question 18

In an ethernet frame what does the type field do?

Answer 18

The Type field is used to determine how the payload is processed by the receiver.

Question 19

What does the IP protocol do?

Answer 19

Packet routing: best path for packet travel within a network.

Addressing: Each device is assigned a unique IP address which identifies the source and destination of the data packets, ensuring that the data is delivered to the correct device.

Question 20

what is ipv4s format?

Answer 20

consist of four octets, each represented by a decimal
number ranging from 0 to 255

Question 21

what is ipv6s format?

Answer 21

eight hextets, each represented by a four-digit
hexadecimal number

Question 22

Function of TCP ?

Answer 22

provides reliable, ordered, and error-checked delivery of a stream of data between applications running on hosts communicating via an IP network.

Question 23

function of UDP

Answer 23

provides unreliable communication, suitable for applications that
prioritise speed over reliability

Question 24

what does a port number do?

Answer 24

specifies a specific application/ process/ service
running on the host device.

Question 25

In addition to an IP address what else does TCP and UDP provide?

Answer 25

a port number.

Question 26

function of transport layer security?

Answer 26

provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications.

Question 27

what are the 2 layers of TLS?

Answer 27

TLS record and the TLS handshake protocols.

Question 28

How is the connection provided by TLS made to be private?

Answer 28

a symmetric-key algorithm is used to encrypt the data transmitted.

Question 29

How is the connection provided by TLS made to be reliable?

Answer 29

each message transmitted includes a message integrity check using a message authentication code to prevent undetected loss or alteration of the data during transmission.

Question 30

name all 5 of HTTP request methods

Answer 30

get post delete put patch

Question 31

what does http get do

Answer 31

Requests a representation of the specified resource. GET should only retrieve data and should have no other effect.

Question 32

what does http post do?

Answer 32

Used to submit an entity to the specified resource, often causing a change in state or side effects on the server.

Question 33

what does http put do?

Answer 33

Replaces all current representations of the target resource with the request payload.

Question 34

what does http delete do?

Answer 34

Removes all current representations of the target resource given by a URI.

Question 35

what does http patch do?

Answer 35

Used to apply partial modifications to a resource.

Question 36

explain the tls handshake procedure

Answer 36

The client and server agree to use TLS and begin a handshake. The client sends a list of supported cipher suites. The server chooses a compatible cipher and hash function and tells the client. The server sends a digital certificate containing its identity, CA information, and public key. The client validates the certificate. The client then generates session keys for secure communication. Once completed, a secure, encrypted connection is established using the session keys. If any step fails, the TLS handshake fails and no connection is made.