3.06 Network protocols

Question 1

What is a network standard

Answer 1

A set of agreed requirements for hardware and software

Question 2

Why are standards important?

Answer 2

Allow manufacturersWh to create products and programs that will be compatible with those from other manufacturers

Question 3

What is a network protocol

Answer 3

A set of rules for how devices communicate and how data is transmitted across a network

Question 4

What are communication protocols

Answer 4

Rules on how communication between two devices must start and end, how the data must be organised, and what devices should do if data goes missing

Question 5

What does “MAC” in MAC address stand for?

Answer 5

Media access control

Question 6

What is a MAC address

Answer 6

A unique identifier of a network-enabled device that cannot be changed

Question 7

What is the format of MAC addresses?

Answer 7

48 or 64-bit binary numbers (these are often converted to hexadecimal numbers)

Question 8

What uses MAC addresses?

Answer 8

used by Ethernet protocol on LANs.

LAN switches read the MAC addresses and use them to direct data to the right device

Question 9

What does “IP” stand for in IP address?

Answer 9

internet protocol

Question 10

What does TCP stand for

Answer 10

transmission control protocol

Question 11

What are IP addresses?

Answer 11

IP addresses are a unique number that identifies a device connected to the internet or a local network.

These are assigned manually or automatically to devices before they can access a network, and are used when sending data between TCP/IP networks (i.e. over the internet)

Question 12

What are the two versions of IP addresses?

Answer 12

IPv4 (uses 32 bits)

IPv6 (uses 128 bits)

Question 13

Why was IPv6 created?

Answer 13

Due to the increasing number of devices that needed unique IP addresses.

IPv4 has 2^32 IP addresses (over 4 billion)

IPv6 has 2^128 IP addresses

Question 14

How are IPv4 and IPv6 addresses split?

Answer 14

IPv6 split into 16-bit chunks, each of which is given as a hexadecimal number

IPv4 split into 8-bit chunks, each given as a denary (base 10) number

Question 15

Describe a TCP/IP protocol

Answer 15

Transmission control protocol (TCP):
The rules for how devices connect to the network. It splits data into packets and reassembles them into the original data once they reach the receiving device. Also checks data is correctly sent and delivered.

Internet protocol (IP):
Responsible for directing packets to their destination across the network

Question 16

What does HTTP stand for and what is it used for?

Answer 16

hyper text transfer protocol

Used by web browsers to access websites and communicate with web servers

Question 17

What does FTP stand for and what is it used for?

Answer 17

File transfer protocol

Used to access, edit and move files between devices on a network

Question 17

What does HTTPS stand for and what is it used for?

Answer 17

HTTP Secure

A more secure version of HTTP. It encrypts all information sent and received

Question 18

What does POP3 stand for and what is it used for?

Answer 18

Post Office Protocol version 3

The server holds the email until you download it, at which point it is deleted from the server

Question 19

What does IMAP stand for and what is it used for?

Answer 19

internet message access protocol

Used to retrieve emails from a server. The server holds the email until you delete it - you only download a copy.

used by most web-based email clients

Question 20

What does SMTP stand for and what is it used for?

Answer 20

simple mail transfer protocol

Used to send emails and transfer emails between servers

Question 21

With respect to protocols, what is a layer?

Answer 21

Layer = a group of protocols with similar functions, where each layer is self-contained - protocols in each layer don’t need to know what’s happening in the other layers, but each layer serves the layer above.

Data can only be passed between adjacent layers, e.gl layer 2 can pass data only to layers 1 and 3

Question 22

Give an example of a layered network protocol

Answer 22

Layer 4. Turning data into websites and other applications (e.g. HTTP, FTP, SMTP)

Layer 3. Splitting data into packets and checking they have been sent and delivered (e.g. TCP)

Layer 2. Making connections between networks and directing data (e.g. IP)

Layer 1. Passing data as electrical signals over the physical network (e.g. ethernet)

Question 23

What are the advantages of using layers (three)?

Answer 23

1, Breaks network communication into manageable pieces, so developers can focus on one area of the network a a time

2. Each layer can be changed without affecting the other layers
3. Having standards for each layer forces companies to make them compatible and universal