1. BTEC level 3
Learning Aim C

2. Pre topic task Make a list and explain why a connection may fail.
What can you do to stop this from happening in the future?
Find some examples of how data is transmitted.

3. Issues relating to transmission of data

4. Protocols used to govern and control data transmission for common tasks

5. Keywords
host – An internet provider that offers an service to its users.
Ping – a test of end to end connectivity, which times the return of an ICMP packet between two hosts
Latency – the ‘delay’ experienced, for example when playing online games (movements made to a character happen a long period time after you made them).
Bit – short for binary digit, smallest component of data
Codec – A device or program that compresses data for faster transmission.

6. Protocols used to govern and control data transmission for common tasks
In IT systems, protocols are essential to allow systems to communicate. It is like a language, a set of rules governing how the communication takes place. The protocol will dictate how the transmission is initiated, how the data is encoded and how it is terminated.
E.g. when you start a conversation and say ‘hello’ you then speak using your language and finally you day ‘goodbye’
TASK – Find out about what protocols are used and what systems they are used in and make a list.

7. Common tasks and the protocols that are used
– POP3, SMTP, IMAP (Exchange)
Voice and video calls over the internet
Web pages
Secure payment systems

8. Security issues
As we use more IT systems as technology advances so does the need for security. There are been a rise in specialists who hack into IT systems and steal / alter data and information.
Recently Tesco (3.5 million pounds stolen), world anti doping agency, Sony PlayStation
It is important that businesses make their systems secure, the data that is sent across the internet can be sensitive or personal and therefore needs to be transferred with care. It is a bit like a delivery truck full of crockery with no packaging.
TASK -

9. Factors affecting bandwidth and latency
Recap –
What is bandwidth?
What is latency?
What can affect the network connection?
Time of day? E.g. Monday at 9:00am people will be logging on to check s
How far are you from the nearest telecommunications exchange
How much data is being transmitted across the network
Wireless or wired

10. Data Compression
Data can be compressed so that it takes up less space and uses less bandwidth, lossy means removing data. Data is lost in order to compress the file.
However if an image files loses too much data the quality will be lower similar to an audio file.
The algorithm removes the data which is less noticeable.
Lossless is the opposite is lossy and reduces the size of the data by removing and filtering any unnecessary bits of data rather than reducing the relevant data.
Codecs are a device which encodes and decodes data and compresses it to make it faster for transmission, compatibility is the main implication, the recipient must be able to decode the data in order to view the image or listen to the audio.

11. Exam Style Question
(c) Many customers worry about the security of personal data when paying for goods and services online. HTTPS is a method used to secure data transmitted between a user and a website. Describe how HTTPS is used to secure transmitted data (4 marks)

12. Mark Scheme Award one mark for any four of the following.
SSL (secure sockets layer) added to 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.