Computing GCSE 1.3.2 Wireless and Wired

What is a network standard?

A set of agreed requirements for hardware and software

Why are network standards important?

they allow manufacturers to create products and programs that will be compatible with products and programs from other manufactures

What is a network protocol?

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

What do communication protocols specify?

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

What does every device need so it can be found on a network?

a unique identifier

What are MAC addresses?

they are assigned to all network enabled devices by the manufacturer, they are unique to the device and cannot be changed

What numbers are MAC addresses?

48 or 64 bit binary numbers, to make them easier they are converted to hexadecimal

What is a MAC address?

the physical address for a device

When are IP addresses used?

When sending data between TCP/IP networks

How are MAC addresses written?

as 12 hexadecimal digits

Are MAC addresses static or dynamic?

they are static and completely unique

How are IP addresses assigned?

either manually or automatically before the device can access the network

What are the two versions of IP addresses?

- IPv4 (32 bits)
- IPv6 (128 bits)

Why was IPv6 created?

due to increasing number of devices that need unique IP addresses

How many IP addresses does each IPv4 and IPv6 have?

IPv4: 2^32, over 4 billion
IPv6: 2^128 addresses

How are IPv6 addresses split?

into 16-bit chunks and each one is given a hexadecimal number

How are IPv4 addresses split?

into 8-bit chunks and each one is given a denary number

What is the TCP/IP protocol?

Protocol made up of 2 different protocols (TCP and IP) which dictates how data is sent between networks

What does TCP stand for?

Transmission Control Protocol

What does TCP set the rules for?

how devices connect on the network

What is TCP in charge of?

its in charge of splitting the data into packets and reassembling the packets back into the original data once they reach the receiving device, it is also responsible for checking the data is correctly sent and delivered

What does IP stand for?

Internet Protocol

What is IP responsible for?

directing packets to their destination across the network

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

stands for: Hyper text transfer protocol
Used for: web browsers to access websites and communicate with web servers

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

Stands for: Hyper text transfer protocol secure
Used for: a more secure version of HTTP, encrypts all info sent and received

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

Stands for: File transfer protocol
Used for: accessing, editing and moving files between devices on a network

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

Stands for: post office protocol
Used for: retrieving emails rom a server, the server holds the email until you download it, at which point it is deleted from the server

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

Stands for: internet message access protocol
Used for: retrieving emails from a server, the server holds the email until you download it at which point it is deleted from the server

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

Stands for: Simple mail transfer protocol
Used for: sending emails and transferring emails between servers

What is a layer?

A group of protocols which have similar functions

What are layers?

they are self contained so protocols in each layer dont need to know whats happening in other layers

What are advantages of using layers?

- it breaks down network communication into manageable pieces
- as they are self-contained, they can be changed without other layers being affected
- having standards for each layers forces companies to make compatible, universal hardware and software

Why do having layers in manageable pieces help developers?

it helps the concentrate on only one area of the network without having to worry about the others

What is encryption?

coding data so that it can only be decoded with the correct key

What is the main benefit of encryption?

intercepted or stolen data is still secure as only the intended readers of the data can unscramble and understand the data

How do computers decrypt data?

they use the special key and a set of instructions to turn the data back to its original form

What are advantages to wired networks?

- more secure
- faster

What are disadvantages of wired networks?

- not portable
- health and safety hazard
- more expensive
- needs planning to set up

What advantages to a Wi-Fi network?

- portable
- cheaper to set up
- longer range than bluetooth
- can connect devices easily

What are disadvantages to a Wi-Fi network?

- too many users slows it down
- you need to be within range
- less secure
- uses a lot of power consumption

What are advantages to a bluetooth network?

- easy or quick to make ad-hoc connections
- good for use on personal devices
- its cheap

What are disadvantages to a bluetooth network?

- uses power consumption
- short range
- can be obstructed

Are IP addresses static or dynamic?

dynamic, they can change

What does an IP address show?

a devices location on a network, it is unique to the network it is on

What is a disadvantage to IPv6?

it isnt fully supported

What do packet headers contain?

the IP address of the sender and the receiver, the packet number so it can be reassembled at the other end

What happens before sending data over a network?

the data is broken down into packets

Why do packets take the quickest route to the destination?

so they dont all have to follow the same route

What is the main benefit of using layers?

one part of the protocol can be changed or re-written without affecting the other parts

What are the 4 layers?

- application: prepares the data using different application protocols
- transport: splits the date into packets or reassembles the packets at the other end
- internet: add the IP address or removes the IP address at the other end
- network: physically transfers the data across the network

What happens in packet switching and what do the packets contain?

messages are broken up into very small pieces, called packets. Each packet consists of two parts:
header and payload