1. Bandwidth What is it? How much do we need? Is it worth it?

2. Niagara falls 567812 litres/sec Water main 5 litres/sec Tap 0.15 litres/sec Think of water and how it gets to your tap Think of how much is flowing at each point

3. Now consider the Internet Internet backbone using optical fibre. 13.271 Giga bits per sec (think Niagara falls of data!) ISP – somewhere between Niagara falls and a mains water supply! Average speed in May 2010 - 5.2 Mega bits per sec

4.  A measure of how much data can be transferred over time, measured in bits per second (bps).  For example - What is bandwidth? Average home broadband speed - 5.2 Mega bits per sec (Mbps) 1 megabit = 1,000,000, 000,000 bits 1 gigabit = 1,000,000,000 billion bits

5. What is a bit?  A bit is the smallest unit of information that can be stored or manipulated on a computer; it consists of either zero or one.  Don’t confuse this with bytes. A byte is a collection of bits. For example, “A” is represented as 01000001

6. Bits vs. bytes  Bytes are usually used to talk about data storage. E.g. a 500 gigabyte hard drive.  Bits are usually used when talking about data communications. E.g. a 5 megabit broadband connection.

7. It’s not just the Internet..  Data is transferred between various parts of the computer and between the computer and peripherals such as hard disks and mobile phones. USB 2.0 – 480 mbps 100x the average home Internet speed!

8. How much do we need? Is bigger always better? No, it depends what you want to use it for!