1.5 Wired and Wireless Networks In this unit you will cover…

Wireless and Encryption In this lesson you will cover: WIFI – What it is and how it works Frequency and channels in WIFI communications Encryption of wireless data

WiFi WiFi stands for Wireless Fidelity WiFi is great – access computer networks without the need for all those pesky wires As with everything in computing, wireless adheres to standards: 802.11 b, g, n or ac These get progressively faster

Wifi Benefits and Drawbacks Ethernet Benefits Wifi Benefits and Drawbacks

How does it work? WiFi uses radio waves to send packets It’s a lot less secure than wired Ethernet as all of your packets are being sent through the air rather than being contained in a cable We can have issues with interference – for example Microwaves and Cordless phones use the same frequency as some WiFi networks

Popty Ping In this picture, every time you microwave something, you’ll lose WiFi (or it will at least slow down) – don’t put your Access Point on a Microwave

Frequency and Channels In radio transmission we use different frequencies – think about tuning an old fashioned FM radio… Radio 1’s frequency is between 97 and 99mhz around the UK… tune your radio to the right frequency and you’ll hear Radio 1.

Frequencies and Channels

Frequencies and Channels WiFi can use two different frequencies 2.4ghz and 5ghz You can only listen to one radio station per frequency, but we can fit loads of WiFi networks in just two frequencies. How? The answer is channels. Because WiFi is digital, we can separate networks into different channels.

Frequencies and Channels Bad news again though – there’s a limited number of channels AND some of them interfere with each other. If your WiFi menu looks like this, there’ll probably be some interference between the networks – this will slow the network down

Frequencies and Channels All of those networks might look something like this in a radio-wave view… Looks a bit crowded, doesn’t it?

Frequencies and Channels This diagram shows the 2.4ghz channels and how they overlap – notice there can only be 3 non-overlapping channels at any one time. Fortunately, most Wireless Access Points automatically change channel depending on what other networks are present This helps to reduce overlap and interference

Encryption Task As wireless transmissions can be intercepted easily, we have to try and protect them Find out: What encryption is How encryption works – some common examples (for WIFI) How “public key” encryption works The advantages and disadvantages of encryption Key words – Asymmetric and symmetric

Encryption When you join a wireless network you’re almost always asked to enter a password. STOP It‘s not a password – it’s a key. Totally different things!

Encryption This man is catching your packets That key isn’t just a way to stop people from stealing your internet connection; it ensures that all of your data that travels through the air is kept secure Remember with WiFi, your data is literally just zooming through the air around you, it’s not locked up safely inside a cable. Anyone can just grab your packets from the air and look at them

Encryption Encryption goes part of the way to protecting your data when it leaves your device (or heading back towards your device) An encryption algorithm scrambles the data – but what if someone learnt how to unscramble it? The answer is the key, the encryption algorithm uses the key to scramble the data; this means that it can only be unscrambled when the correct key is used

Encryption Encryption doesn’t stop people from grabbing your packets from the air; they can still grab every single one The difference is that the packets are absolutely useless to them, there’s no way they can make any sense of them without the correct algorithm and key Encryption has become a hot topic in the news over the last few years…

Encryption Research either of the following: FBI Apple Encryption Dispute UK Government and Whatsapp Encryption Produce a PowerPoint explaining (a slide for each of the following) What it’s all about What the government or FBI want changed What would be good and bad about this What would be the impact to normal people?