1. Computer Networks – IP addresses and binary Week 4 1010

2. Starter – complete the introduction by matching the words with the numbered gaps, write the number & word on your whiteboard 1010 IP binary (use twice) on electrical off data electricity 192.25.48.255 Computers can only represent ………(1)…….. using 1s and 0s. This number system is called ………(2)……….. This is because they are ………(3)……………. devices and ………(4)..…………..is either …(5)….(=1) or …(6)…. (=0). All devices connected to a network need an …(7)….. address which to us would look something like………………(8)………………………. However, a computer can only recognise this when it is converted to………(9)………… so that’s what we’re doing today!

3. In today’s lesson: Success Criteria ALL: Successfully convert smaller numbers to/from binary. Understand that each device connected to a network needs an IP address. MOST: Successfully convert IP addresses to and from binary. Be able to explain why a device needs an IP address to connect to a network. SOME: Be able to explain why a new system of IP addresses has to be used. Be able to convert to/from binary numbers and write an IP address as a binary number Understand why devices need an IP address Understand the issue with the current format of IP addresses Lesson Objectives 1010

4. Literacy -Today’s key words IP address Binary Denary IPv4 IPv6 1010

5. Can you remember what an IP address looks like? An IP address is a 32-bit numeric address written as four bytes separated by full stops (these are called octets). Each number can be 0 to 255. For example, 19.163.10.240 could be an IP address. Within your home network, your devices could be assigned IP addresses at random as long as each one is unique. However, connecting your home network or a server to the Internet via your ISP requires using registered IP addresses (called Internet addresses) to avoid duplicates. Some combinations such as 0000.0000.0000.0000 or 255.255.255.255 are restricted 1010

6. IP addresses and binary As computers only use binary, an IP address must be stored as a binary number for the computer/network’s use, but can is written as numbers that we recognise for human users. For example: 172. 16. 254. 1 10101100.00010000.11111110. 00000001 1010 Byte 1 (the network) Byte 2 Byte 3 Byte 4 (the device)

7. You might need a refresher on binary so here we go: We use Base 10 so everything goes up in 10s and we can use all the numbers from 0 to 9 = (0 x 10000) + (1 x 100) + (6 x 10) + (1 x 8) = 168 Binary uses Base 2 so everything goes up in 2s and only uses 1 or 0. =(1 x 128) + (0 x 64) + (1 x 32) + (1 x 16) + (0 x 8) + ( 0 X 4) ( 1 X 2) + ( 0 x 1) = 168 1000100101 0168 1286432168421 10110010 1010

8. 8 An Example The value of binary 01100001 is decimal 105. This is worked out below: 1286432168421 ------------------------------------------------------------------------------- 01101001 1 X 1= 1 0 X 2 = 0 0 X 4 = 0 1 X 8 = 8 0 X 16 = 0 1 X 32 = 32 1 X 64 = 64 0 X 128 = 0 ---- Total them to get the Answer: 105

9. 9 Another example The value of binary 10011100 is decimal 156. This is worked out below: 1286432168421 ---------------------------------------------------------------------- 10011100 0 X 1= 0 0 X 2 = 0 1 X 4 = 4 1 X 8 = 8 1 X 16 = 16 0 X 32 = 0 0 X 64 = 0 1 X 128 = 128 ---- Total them to get the Answer: 156

10. Binary Conversions Learning Check …Easy…. On your whiteboard, convert these numbers from binary to denary: 1.1101 2.1001 3.1010 4.1000 5.0101 1286432168421 1010

11. Binary Conversions Learning Check …Harder …. On your whiteboard, convert these numbers from binary to denary: 1.011101 2.101001 3.101010 4.011000 5.100101 1286432168421 1010

12. Binary Conversions Learning Check …Hardest …. On your whiteboard, convert these numbers from binary to denary: 1.10011101 2.01101001 3.11101010 4.10011000 5.11100101 1286432168421 1010

13. Binary Conversions Learning Check …Easy-ish…. On your whiteboard, convert these numbers from denary to binary: 1.12 2.28 3.46 4.68 5.130 1286432168421 1010

14. Binary Conversions Learning Check …Harder …. On your whiteboard, convert these numbers from binary to denary: 1.55 2.76 3.219 4.178 5.255 1286432168421 1010

15. So how does this work with IP addresses? 1010

16. How many IP addresses are there? This 32-bit IP address system is also known as IPv4. It allows for 2 32 or around 4 billion unique addresses. But …… There are currently billions of devices connected to the Internet. This number is set to grow with the increase in internet capable smart devices and machines (e.g. televisions, air conditioners, washing machines, lights, cars etc.). All will have to connect and communicate through some form of IP Address. 1010

17. There’s an IP Address shortage While nearly 4 billion unique combinations might sound like a lot, the huge growth in internet connected devices means we have nearly run out of available IPv4 addresses. Most devices are “loaned” a dynamic IP address for a period of time, apart from servers which get a static IP address that doesn’t change. So, IPv6 is now coming into use. IPv6 uses 16 bits for each section of the address, creating a 128-bit address. This allows for a MASSIVE number of IP addresses – in fact, almost 80 octillion or a thousand quadrillion or 10 27 unique IP addresses. 1010

18. What do IPv6 IP addresses look like? IPv6 addresses are 128-bit IP address written in hexadecimal and separated by colons. An example IPv6 address could be written like this: 3ffe:1900:4545:3:200:f8ff:fe21:67cf As an extension task, you can find out more about hexadecimal numbers, we’re not covering them today!!! 1010

19. What to do now Make sure you have a folder in your work area called Computer Networks Log into Moodle Go to ICT & Computing > Year 8 > Digital Networks > Week 4 Download to your documents the worksheet called IP Addresses and Binary (not to downloads, put it in your correct folder!) Open it and complete it. Print by end of lesson! 1010

20. Q6 answers 1.88.70.244.38 = Vodafone, Germany 2.Microsoft 3.Amazon (actually it’s for intu the Trafford Centre, whose website is hosted by them at that IP address) 4.23.203.220.68 = McDonalds, America Because websites are often on shared servers, a search to find information about the IP address doesn’t necessarily give you the name of each company, it gives you the name of the hosting company. Also, an IP address may change, so it could be that an IP address won’t work Not all IP addresses are listed in the databases used by the “lookup” tools online

21. Plenary – how well have you done today? Which Success Criteria have you met? Can you……? ALL: Successfully convert smaller numbers to/from binary. Understand that each device connected to a network needs an IP address. MOST: Successfully convert IP addresses to and from binary. Be able to explain why a device needs an IP address to connect to a network. SOME: Be able to explain why a new system of IP addresses has to be used. 1010