T3 - Protocols and layers:

Question 1

Protocols

Answer 1

• set of rules

Question 2

HTTP

Answer 2

– Hypertext Transfer Protocol

Question 3

HTTPS –

Answer 3

Hypertext Transfer Protocol Secure

Question 4

FTP –

Answer 4

File Transfer Protocol

Question 5

POP –

Answer 5

Post Office Protocol

Question 6

IMAP –

Answer 6

Internet Message Access Protocol

Question 7

SMTP –

Answer 7

Simple Mail Transfer Protocol

Question 8

TCP/IP –

Answer 8

Transmission Control Protocol /
Internet Protocol

Question 9

HTTP use

Answer 9

used for accessing and receiving web pages via the Internet - written in HTML
protocol requests a web page from the
web server
The server sends its response with the web page

Question 10

HTTPS (secure HTTP) use

Answer 10

encrypts the information so that it cannot be understood by an eavesdropper

Question 11

Websites using HTTPS =

Answer 11

Banks or online shops

Question 12

FTP: role

Answer 12

used for sending or retrieving files to or from a FTP server

Question 13

How email works:

Answer 13

email is sent from a computer it will first be sent to a mail server using the SMTP protocol
When it reaches the destination mail server it is stored
The user’s computer uses POP or IMAP to access the email

Question 14

POP and IMAP:

Answer 14

email retrieval protocols fetch message data and attachments from your remote mail server

Question 15

POP: role

Answer 15

will download every new message to your local device and delete from local server

Question 16

IMAP: role

Answer 16

will leave the messages on a server.
They can be accessed by multiple devices
they only are removed if the user deletes them

Question 17

SMTP: role

Answer 17

email protocol used for sending email
Email software sends the
email to the SMTP server used by the company or individual
the email arrives at the destination mail server

Question 18

TCP protocol: role

Answer 18

Breaks up messages sent over the Internet into small chunks called packets
Reassembles the packets at the other end
Detects errors
Resends lost messages

Question 19

IP protocol: role

Answer 19

Routes the individual packets from one IP address to another

Question 20

Order of layers:

Answer 20

Application layer (SMTP, FTP and HTTP )
Transport layer (TCP)
Internet layer (Routers and IP)
Link layer (MAC (Media Access Control), Ethernet, Wi-Fi

Question 21

Application layer:

Answer 21

email clients and web browsers create data to send in this layer

Question 22

Transport layers:

Answer 22

creates the connection between two computers, or ‘hosts’
Data is then divided up into packets and given a packet number
Packets are reassembled by the recipient’s Transport layer
Lost packets are resent

Question 23

Internet layer:

Answer 23

responsible for routing packets
Source and destination addresses are written on to the packets ready for transmission

Question 24

Receiving data: order of layers

Answer 24

The link layer
The Internet layer
The Transport layer
The Application

Question 25

Advantages of layers:

Answer 25

Self-contained
functionality of one layer can be changed without affecting the functionality of other layers
Different hardware or software operates on a particular layer = interoperability

Question 26

Receiving data: link layer

Answer 26

removes the MAC address and passes packets up to the Internet layer

Question 27

Receiving data: internet layer

Answer 27

The Internet layer removes the IP addresses and passes packets up to the Transport layer

Question 28

Receiving data: transport layer

Answer 28

The Transport layer reassembles the packets and passes the data to the Application layer

Question 29

Receiving data: application layer

Answer 29

The Application layer uses the correct protocol to correctly display the data, web page or email for the user