Revision

Protocols

1. What does a protocol define?

 

2. Give the full name for the following protocols:

a. HTTPS

b. IMAP

c. POP

d. HTTP

e. SMTP

 

3. What is the purpose of the IMAP and POP protocols? 

 

4. What does the S add to the HTTP protocol? 

Protocols

1. A protocol defines a set of rules for a computer to follow when connecting to the internet.

2. Give the full name for the following protocols:

a. HyperText Transfer Protocol Secure

b. Internet Message Access Protocol

c. Post Office Protocol

d. HyperText Transfer Protocol

e. Simple Mail Transfer Protocol

3. IMAP and POP are used to download email messages from the server onto the device you are using.

4. The S stands for secure which means an addition Secure Socket Layer has been added to the protocol to encrypt the data that is being transmitted. 

Protocols

How email works:

 

  • Mail servers pass on (via SMTP) or store emails until they are collected 
  • You must log in to a mail server to collect your mail
  • An IMAP connection will give you access to your email on the server, whereas;
  • A POP connection will download the email to the device you are logged into so it then exists only on that device

Protocols

Voice over Internet Protocols (VoIP)

 

H.323 protocols suite is used to control the setup, management and termination of video and audio calls over the internet.

 

Media Gateway Control Protocol (MGCP) is a text-based protocol consisting of commands and responses, creating a centralised gateway for administration. This protocol is used to convert traditional electronic media to the internet protocol network.

 

Simple Gateway Control Protocol (SGCP) is the predecessor to the MGCP, which is used to connect residential telephones.

Protocols

TCP/IP

 

Transmission Control Protocol (TCP) is used to break up messages into packets, reassembles those packets at the other end of the transmission, detects any errors that may have occurred and will resend any lost packets.

 

Internet Protocol (IP) is in charge of setting up the route for the individual packets to follow via the network to reach their destination.

Protocols

TCP/IP

The protocol stack defines four layers in which different protocols operate to pass data packets across a network.

These are the:

  • Application layer, to allow access to network resources. Such as the HTTP and SMTP.
  • Transport layer, to provide reliable processes to process message and error delivery. Such as the TCP.
  • Network layer, to move packets from the source to the destination and to provide internetworking. Such as the IP. 
  • Link layer, to define how packets are moved around the network. Such as Ethernet protocols. 

Protocols

HTTP & HTTPS

 

 

Another type of security you can add instead of SSL is a Transport Layer Security (TLS).

Protocols

File Transfer Protocol

 

This is used to transmit data to and from a remote server or computer, e.g., accessing your files on a cloud server.

Exam Question

Many customers worry about the security of personal data when paying for good and services online. HTTPS is a method used to secure data transmitted between a user and a website. 

Describe how HTTPS is used to securely transmit data. (4)

Exam Question Answer 

Award one mark for any four of the following.

 

SSL (secure sockets layer) added to the HTTP to add layer of security (to give HTTPS)/security certificate. (1)

SSL uses encryption to secure the data (1)

Only those with the 'key' can read the data. (1)

SSL certificate provides private communication channels for data transmission/only the website server and the customer's device. (1) 

Accept any other relevant phrasing/wording. 

Operating Systems 

An operating system is software that manages a computer's hardware and provides a user interface.

 

What can an operating system manage in a computer? 

 

Operating Systems 

An operating system is software that manages a computer's hardware and provides a user interface.

 

What can an operating system manage in a computer? 

  • The memory
  • multitasking
  • any peripheral devices
  • file management
  • user access rights

Operating Systems 

Types of User interfaces: 

  • GUI: Graphical User Interface
    • WIMP: Windows, Icons, Menus and Pointers
  • Menu driven interface
  • CLI: Command line interface
    • Just text, like the windows command prompt
  • Voice Activated 
  • Real-time
    • Sensors detect inputs, actuators output actions

Exam Question

Josie’s new laptop has a pre-installed operating system.
Describe the role of the operating system in memory management. (3)

Exam Question Answer

Award one mark for each of the following, up to a maximum of three marks.

The memory manager needs to allocate blocks of memory to applications (and data) (1) the memory manager should allow many applications to occupy memory at the same time (1) the applications need to be protected from one another so that they do not overwrite each other. (1)