1 00:00:12,560 --> 00:00:14,080 Now networks can get really big. 2 00:00:14,110 --> 00:00:16,149 Biggest network that we know of today. 3 00:00:16,149 --> 00:00:21,850 Unless you know about aliens having a bigger network somewhere out there in space is the Internet. 4 00:00:21,850 --> 00:00:25,090 So the Internet is the biggest network that we have on Earth today. 5 00:00:25,090 --> 00:00:27,570 But a network doesn't have to be very big. 6 00:00:27,940 --> 00:00:31,610 A small network would simply consist of two computers. 7 00:00:32,140 --> 00:00:39,160 So in this example I've got two Windows laptops previously as I mentioned I could copy a file onto this 8 00:00:39,220 --> 00:00:40,550 USB drive. 9 00:00:40,840 --> 00:00:48,600 So copy a file from this computer onto the drive and then put it into the second computer and then copy 10 00:00:48,630 --> 00:00:50,880 the file onto this computer. 11 00:00:50,970 --> 00:00:59,100 So that's how I could share information from one computer to another without a network. 12 00:00:59,200 --> 00:01:05,550 But in its most basic form a computer network will use something like a cable. 13 00:01:05,560 --> 00:01:08,730 This is a copper Ethernet cable. 14 00:01:08,740 --> 00:01:14,680 This is what's called UTP or Unshielded Twisted Pair copper cable. 15 00:01:14,740 --> 00:01:18,320 You've probably come across these types of connectors in the real world. 16 00:01:18,340 --> 00:01:20,800 This is known as an RJ45 connector. 17 00:01:20,800 --> 00:01:24,250 Now it does have a different name but we won't get into that right now. 18 00:01:24,250 --> 00:01:27,790 This is commonly referred to as an RJ45 connector. 19 00:01:27,910 --> 00:01:33,790 So if you talk about RJ45 in a networking context people will know what you're talking about. 20 00:01:33,790 --> 00:01:39,280 So I could as an example take this cable and then plug it into this laptop. 21 00:01:39,280 --> 00:01:47,260 Now this is an older laptop so it has a built-in Network Interface Cards so I can take an RJ45 connector 22 00:01:47,530 --> 00:01:50,460 and plug it directly into this computer. 23 00:01:50,500 --> 00:01:58,120 This laptop however on the right is a newer laptop and like a lot of newer laptops and Mac books it 24 00:01:58,120 --> 00:02:03,690 doesn't have any RJ45 Network Interface Cards. 25 00:02:03,710 --> 00:02:10,930 Now a Network Interface Card or NIC is how we connect to the physical network or wireless network. 26 00:02:10,960 --> 00:02:17,290 It's basically a card that's either inserted into a laptop or is built into a laptop that has what's 27 00:02:17,290 --> 00:02:24,070 called a MAC address or Media Access Control address on Ethernet which is the technology that we generally 28 00:02:24,070 --> 00:02:30,490 use today on wireless devices are known by what's called a MAC address. 29 00:02:30,490 --> 00:02:37,270 So here's an example of a very old Network Interface Card this Network Interface Card supports 30 00:02:37,300 --> 00:02:42,980 older technologies such as 10base5 the first type of Ethernet that was ever developed supports 31 00:02:43,000 --> 00:02:50,270 10base2 and it also supports an RJ45 connector using UTP or Unshielded Twisted Pair. 32 00:02:50,350 --> 00:02:53,250 This would be inserted in a computer. 33 00:02:53,340 --> 00:02:54,530 Now that's really old. 34 00:02:54,550 --> 00:03:01,070 Today we have more modern unshielded such as this one only supports RJ45. 35 00:03:01,120 --> 00:03:02,700 It's a lot smaller. 36 00:03:02,800 --> 00:03:07,640 And then this is an example of a Network Interface Card that would go in a Raspberry Pi as an example. 37 00:03:07,660 --> 00:03:09,580 This only supports Wi-Fi. 38 00:03:09,580 --> 00:03:12,760 I mean you can't connect Ethernet to this. 39 00:03:12,760 --> 00:03:21,610 So on a laptop like this what I could do is I could use a USB to RJ45 Network Interface Card 40 00:03:21,730 --> 00:03:25,990 So this is an adapter that converts a USB to RJ 45. 41 00:03:25,990 --> 00:03:32,780 And then what I can do is plug the Ethernet cable in here and what I have now is essentially a network. 42 00:03:32,920 --> 00:03:37,060 I have a network consisting of two windows computers 43 00:03:40,800 --> 00:03:45,060 and I'll now be able to share files from one computer to the other. 44 00:03:45,060 --> 00:03:47,820 But it's a lot of hassle a lot of work setting this up. 45 00:03:47,910 --> 00:03:51,040 But that's an example of an Ethernet network. 46 00:03:51,100 --> 00:03:54,400 where I have two computers connected using a physical cable 47 00:03:54,570 --> 00:04:03,310 In this example what's called Cat 5e cabling unshielded-twisted pair RJ45 connectors on the end. 48 00:04:03,330 --> 00:04:05,720 That's an example of a very basic network. 49 00:04:06,570 --> 00:04:09,330 But if I told a young person today. 50 00:04:09,540 --> 00:04:17,730 So let's say a teenager to set up a network between their devices using cabling like that they'd probably 51 00:04:17,730 --> 00:04:21,730 think I'm crazy because what we tend to use today is Wi-Fi. 52 00:04:21,750 --> 00:04:29,040 Wi-Fi is an example of using the air for transmission of data from one device to the other makes life 53 00:04:29,040 --> 00:04:30,180 a lot easier 54 00:04:30,210 --> 00:04:37,310 in many ways. People today expect that it's easy to share information from one device to another. 55 00:04:37,320 --> 00:04:39,050 In this example I've got two iPhones. 56 00:04:39,090 --> 00:04:42,760 I mean how would I physically plug a cable into one of these phones. 57 00:04:42,780 --> 00:04:52,530 They don't have RJ45 connectors I don't have a USB to Ethernet port that I can use to plug an Ethernet 58 00:04:52,530 --> 00:04:54,630 cable into the iPhone. 59 00:04:54,630 --> 00:05:00,220 I could use the lightning port but people today wouldn't be happy with that. 60 00:05:00,270 --> 00:05:04,290 They expect it to just work and work very easily. 61 00:05:04,290 --> 00:05:10,470 And the technologies that we're going to be using to share files from one phone to another are Wi-Fi 62 00:05:10,560 --> 00:05:11,860 as well as Bluetooth. 63 00:05:11,940 --> 00:05:20,450 So as an example on this phone here's a picture I'm going to share that picture using airdrop notice 64 00:05:20,450 --> 00:05:28,820 it tells me that Bluetooth is off. I need Bluetooth to allow this device to share the file with other 65 00:05:28,820 --> 00:05:29,800 devices. 66 00:05:29,810 --> 00:05:36,290 Now it's picked up two devices I've got a iPhone Blue which is the phone on the right as well as my 67 00:05:36,290 --> 00:05:38,230 MacBook which is in front of me. 68 00:05:38,480 --> 00:05:41,650 So I'm going to select the iPhone. 69 00:05:42,290 --> 00:05:46,200 And what happens now is the file is shared from one phone to the other. 70 00:05:46,430 --> 00:05:53,570 So by leveraging Wi-Fi and Bluetooth I can share a file from one phone to the other. 71 00:05:53,660 --> 00:06:00,170 That's an example of file sharing I'm sharing a file which in this example is a picture from one phone 72 00:06:00,230 --> 00:06:01,430 to the other. 73 00:06:01,430 --> 00:06:10,010 And the medium or media that I'm using is the air I'm sharing data from one device to another using 74 00:06:10,010 --> 00:06:13,990 Waze through the air just like I'm speaking to you. 75 00:06:14,120 --> 00:06:20,690 And what's happening is a microphone is picking up the waves that I'm making with my vocal cords. 76 00:06:20,690 --> 00:06:24,200 Basically speaking into the air making waves. 77 00:06:24,200 --> 00:06:26,930 That's then digitized by microphone. 78 00:06:26,930 --> 00:06:34,790 Same idea here a digital file on a phone is modulated in the air sent across through airwaves from one 79 00:06:34,790 --> 00:06:40,420 device to the other this device to modulate it and creates the file on the other side. 80 00:06:40,580 --> 00:06:48,230 So I'm transmitting a resource a file from one device to the other using the air. 81 00:06:48,230 --> 00:06:51,980 In this example that's an example of a network. 82 00:06:52,010 --> 00:06:58,150 I've got a network of two devices where one device is sharing a resource with another device.