WEBVTT - What is a router? 0:00:00.280 --> 0:00:02.960 Brought to you by the reinvented two thousand twelve Camray. 0:00:03.160 --> 0:00:08.840 It's ready. Are you get in touch with technology? With 0:00:09.000 --> 0:00:17.560 tech Stuff from how stuff works dot com. Hello everyone, 0:00:17.640 --> 0:00:20.560 welcome to tech stuff. My name is Chris Polette. I'm 0:00:20.600 --> 0:00:23.400 an editor at how stuff works dot com, and as usual, 0:00:23.960 --> 0:00:26.960 sitting across from me, I have senior writer Jonathan Strickland. 0:00:27.200 --> 0:00:31.920 We're on a road to nowhere, which just goes to 0:00:31.960 --> 0:00:33.880 show you that we're not a couple of talking heads. 0:00:33.960 --> 0:00:37.199 That's right, Before we get into this topic, we have 0:00:37.640 --> 0:00:40.160 actually it's a two fur First, we have a little 0:00:40.720 --> 0:00:49.080 listener mail. This listener mail comes from Sam, and Sam says, Hello, 0:00:49.159 --> 0:00:51.080 John and Chris. I really enjoy your show and I 0:00:51.120 --> 0:00:53.880 appreciate all the wonderful information you provide about various tech 0:00:53.960 --> 0:00:56.000 Keep up the good work, could you, guys, perhaps to 0:00:56.040 --> 0:00:58.400 a podcast that covers how network routers such as links 0:00:58.440 --> 0:01:01.160 Us and other's work for and their role in office 0:01:01.160 --> 0:01:03.240 and home networks. That'd be swell if you did. Thank 0:01:03.240 --> 0:01:06.559 you guys for making such entertaining yet informative podcast. Cheers. PS. 0:01:06.760 --> 0:01:09.679 Is there any chance that the old listener mail audio 0:01:09.720 --> 0:01:12.360 clip might be played again? You know, the one with 0:01:12.440 --> 0:01:14.360 the annoying alarm. I like the new one, and I 0:01:14.360 --> 0:01:15.840 know it is stuck, but there are times where I 0:01:15.920 --> 0:01:19.840 yearned to hear the old one. Sam. This is for you. 0:01:20.040 --> 0:01:24.080 Everyone else, please turn down the volume on your your 0:01:24.160 --> 0:01:27.640 various playback devices. You have been warned, and now that 0:01:27.720 --> 0:01:31.120 I have warned you, here comes a little old school 0:01:31.160 --> 0:01:41.160 sound effect for listener. But on top of the listener 0:01:41.160 --> 0:01:43.760 mail that we just read from Sam from Austin, Texas, 0:01:43.800 --> 0:01:48.000 we also had a little Facebook feedback you be This 0:01:48.080 --> 0:01:49.840 comes from Scott, who says, Hey, I was wondering if 0:01:49.840 --> 0:01:52.240 you guys could do a podcast about routers, the different 0:01:52.320 --> 0:01:55.640 uses for them and which is best for gaming, streaming, video, etcetera. 0:01:55.840 --> 0:01:58.200 Thanks so much. Your episode on I p V six 0:01:58.280 --> 0:02:00.960 was great and the number of IP address as was nuts. 0:02:01.080 --> 0:02:03.120 You're telling me, Scott, I'm still trying to get my 0:02:03.160 --> 0:02:06.400 breath back. So we are going to talk about routers. 0:02:06.400 --> 0:02:09.000 And before we get too far into this, I want 0:02:09.040 --> 0:02:11.840 to say we have some great articles on how stuff 0:02:11.880 --> 0:02:14.240 works dot Com about routers, so if you want to 0:02:14.280 --> 0:02:17.640 get more information, I recommend checking out how routers work, 0:02:17.680 --> 0:02:20.600 also how network address translation works. Both of those are 0:02:20.600 --> 0:02:23.920 going to be important in this discussion. Um, so let's 0:02:23.960 --> 0:02:26.639 talk about what a roller is and what it does 0:02:26.720 --> 0:02:31.920 and why it's important, yes, and talking about what value 0:02:31.960 --> 0:02:34.680 it has to the Internet. Let's just say there wouldn't 0:02:34.720 --> 0:02:40.840 be one without routers because you know, of course, the 0:02:40.880 --> 0:02:45.079 Internet is a network of computers. It's just networks. Yes, 0:02:45.120 --> 0:02:47.960 it's exactly. It's a it's a basically, it's a vast 0:02:48.639 --> 0:02:52.639 system of computers talking to one another via multiple networks 0:02:52.840 --> 0:02:55.840 and protocols. So yes, well yeah, they use the protocols 0:02:55.840 --> 0:02:57.880 to talk to us. But yeah, I mean you have 0:02:58.560 --> 0:03:01.160 you might have only one computer in your house and 0:03:01.240 --> 0:03:04.480 it hooks up to you know, the networks at the 0:03:04.520 --> 0:03:08.120 Internet service provider, and then those go to other networks 0:03:08.160 --> 0:03:10.160 and it just goes on and on and on. Or 0:03:10.200 --> 0:03:13.519 you might even have multiple computers in your house running 0:03:13.520 --> 0:03:16.880 on another network which is attached to the other networks. 0:03:17.320 --> 0:03:19.840 That's why they call it a cloud, because there's no 0:03:20.240 --> 0:03:22.880 definite shape to the Internet. It all. It all depends 0:03:22.919 --> 0:03:25.360 on what's on and what's off at any given time, 0:03:25.919 --> 0:03:28.480 and these routers make it possible, especially when you do 0:03:28.600 --> 0:03:31.200 have one line coming into your house and you have 0:03:31.360 --> 0:03:35.400 multiple computers. Yeah, So what routers allow is the transfer 0:03:35.440 --> 0:03:40.080 of information across different layers of communication. Now, what I 0:03:40.120 --> 0:03:43.680 mean by that is that the Open Systems inter Connection 0:03:43.800 --> 0:03:48.360 or os I model of communication divides up communication into 0:03:48.600 --> 0:03:52.040 seven layers. And uh, really we're just going to be 0:03:52.080 --> 0:03:54.680 thinking about the first three layers here. Actually now I'm 0:03:54.680 --> 0:03:57.520 thinking about seven layer bars. Yeah, I'm thinking about seven 0:03:57.560 --> 0:04:02.920 layer dip so um dip so. The the the seven 0:04:03.000 --> 0:04:05.800 layers are. This was a system that was proposed by 0:04:05.920 --> 0:04:09.960 Charles Bachman of a Honeywell Information Services. Honeywell, of course, 0:04:10.000 --> 0:04:12.440 is one of those big names that's important in uh 0:04:12.480 --> 0:04:15.560 in computer science. Yeah, they they've done all kinds of 0:04:15.560 --> 0:04:20.480 technological things. Yes, So the seven layers are sort of 0:04:20.560 --> 0:04:23.719 as a concepts so that you can break down what 0:04:23.880 --> 0:04:28.520 sort of communication happens between various components within a communication system. 0:04:28.560 --> 0:04:30.520 And it's uh so that you can really figure out, 0:04:30.520 --> 0:04:33.200 all right, well, how do we have these various layers 0:04:33.240 --> 0:04:36.359 interact with one another, which ones need to be, you know, 0:04:36.440 --> 0:04:39.360 segregated from the rest and uh and just kind of 0:04:39.400 --> 0:04:42.760 a way of defining it, at least from an ideal 0:04:43.160 --> 0:04:47.080 perspective as opposed to necessarily a physical one. But layer 0:04:47.160 --> 0:04:49.520 one is what we call the bit layer it's the 0:04:49.520 --> 0:04:53.120 physical layer of data communication. So we're talking about physical 0:04:53.160 --> 0:04:56.680 elements such as pens and uh the voltage, it's act 0:04:56.800 --> 0:05:00.040 also electrical layout. It's the voltage that you need it 0:05:00.160 --> 0:05:04.560 transfer information. And really you're talking about a single device 0:05:05.320 --> 0:05:09.520 communicating through some sort of medium. So this is where 0:05:09.520 --> 0:05:12.760 we were talking about one device. We're not connecting it 0:05:12.800 --> 0:05:16.640 to anything else at on a layer one layer of communication. 0:05:17.080 --> 0:05:21.680 Layer two is where we start talking about communication between devices, 0:05:22.040 --> 0:05:24.920 and in this case we're talking about communication between devices 0:05:24.960 --> 0:05:29.000 within a local area network or land. All right, so 0:05:29.720 --> 0:05:32.960 a land you do not need a router. We actually 0:05:32.960 --> 0:05:37.440 had another fellow right in UM recently on on our 0:05:37.440 --> 0:05:41.880 Facebook page, I posted a quiz about routers, and he 0:05:42.000 --> 0:05:45.320 pointed out that actually this is Carl who said this 0:05:45.440 --> 0:05:47.839 is called me pedantic. But question one, A home network 0:05:47.880 --> 0:05:50.960 does not require a router to operate either. Carl is 0:05:51.000 --> 0:05:53.960 absolutely correct. You do not need a router to allow 0:05:54.000 --> 0:05:57.160 communication within a local area network. You need a switch 0:05:57.600 --> 0:05:59.720 that can switch the data back and forth, but you 0:05:59.760 --> 0:06:02.920 don't need a router. Right, So this is layer to 0:06:03.120 --> 0:06:05.520 all that all that communication within layer two within a 0:06:05.560 --> 0:06:10.520 local area network, a single network can be uh controlled 0:06:10.520 --> 0:06:12.760 through a switch. You don't have to worry about a 0:06:12.839 --> 0:06:15.920 router at that point. Now, if you want to communicate 0:06:15.960 --> 0:06:19.360 to a device, it's on another network. This is where 0:06:19.360 --> 0:06:22.640 the Internet comes in. The Internet is that network of networks. 0:06:22.680 --> 0:06:25.520 So let's say I want to visit a website and 0:06:25.560 --> 0:06:29.400 the server that has that websites information on it is 0:06:29.480 --> 0:06:31.919 not on my local area network, but is on some 0:06:32.160 --> 0:06:35.279 other network, possibly on the other side of the world. 0:06:35.920 --> 0:06:38.240 That's when you need a router, because what the router 0:06:38.400 --> 0:06:42.160 does is it controls the the information moving from your 0:06:42.200 --> 0:06:46.200 local area network to the Internet so that it will 0:06:46.240 --> 0:06:49.320 go to the proper place. And it also receives information 0:06:49.360 --> 0:06:52.320 from the Internet and transfers it to your local area 0:06:52.360 --> 0:06:54.680 network so that you can view it or interact with 0:06:54.680 --> 0:06:59.160 it in whatever way. So that's the basic purpose of 0:06:59.200 --> 0:07:02.680 a router, uh And it's you know, when you break 0:07:02.720 --> 0:07:04.479 it down that way, it kind of it makes it 0:07:04.520 --> 0:07:07.040 easier to understand why routers are important. Without a router, 0:07:07.560 --> 0:07:10.280 you would not be able to have this this data 0:07:10.360 --> 0:07:14.240 transfer between a larger network or or a computer on 0:07:14.320 --> 0:07:16.760 another network and your computer you would just have You'd 0:07:16.800 --> 0:07:19.560 be able to have communication through a local system, but 0:07:19.640 --> 0:07:22.760 not through a global system. Unless you have a really 0:07:22.800 --> 0:07:27.400 long cable. Yeah. That's especially important for the Internet because 0:07:27.400 --> 0:07:30.040 as as you will remember, or at least as a 0:07:30.080 --> 0:07:33.360 long time listeners will remember, Uh, traffic on the Internet 0:07:33.400 --> 0:07:39.760 goes in little uh pieces or packets. They're actually called packets, um, 0:07:39.800 --> 0:07:43.840 and they're sent uh redundantly. So you know, you might 0:07:43.880 --> 0:07:46.960 take a file, uh say, an email and break it 0:07:47.000 --> 0:07:50.640 down into a series of packets. Each of those has 0:07:50.720 --> 0:07:55.240 some information that tells where it's going, UM, where it's 0:07:55.280 --> 0:07:58.040 coming from, and what piece it is. It might be, 0:07:58.080 --> 0:08:02.480 you know, piece three of packet three of forty, let's say, um, 0:08:02.520 --> 0:08:05.320 so it tells uh the network where to send it 0:08:05.360 --> 0:08:07.120 and how to reassemble it when it gets there. On 0:08:07.160 --> 0:08:11.040 the other side, Well, the thing is, uh, it might say, okay, well, 0:08:11.160 --> 0:08:14.280 I'm going from uh computer A to computer B, to 0:08:14.360 --> 0:08:17.680 computer C to computer D. Well, all of a sudden, 0:08:17.760 --> 0:08:20.920 there's a power failure at computer C, so it goes 0:08:20.960 --> 0:08:25.559 from A to B. Oh it's stuck. Well, in the Internet, Uh, 0:08:25.600 --> 0:08:28.240 it's set up where the packets can be sent and 0:08:28.320 --> 0:08:31.320 re routed around computer C. So you might go to 0:08:31.320 --> 0:08:34.880 computer F and then back to computer D. Because they 0:08:34.880 --> 0:08:37.880 can be sent at multiple directions. At the same time, 0:08:37.920 --> 0:08:40.520 and then you know with the idea that one set 0:08:40.600 --> 0:08:42.720 of packets will be reassembled into the file on the 0:08:42.720 --> 0:08:46.600 other end. And the router is crucial to making this happen. Yeah, 0:08:46.760 --> 0:08:50.360 Routers have this thing called a routing table, and routing 0:08:50.400 --> 0:08:55.240 table is essentially a guide saying this is where, this 0:08:55.280 --> 0:08:57.600 is the direction you need to send packets in order 0:08:57.679 --> 0:09:00.760 for information to come to go from to this machine 0:09:00.920 --> 0:09:03.880 and get to that machine. So machine A and machine 0:09:03.880 --> 0:09:06.720 beat will say, alright, So a routing table will in 0:09:06.800 --> 0:09:11.199 general give the fastest uh route. Now, the fastest route 0:09:11.240 --> 0:09:15.120 is not necessarily the shortest route, true, And it's the 0:09:15.160 --> 0:09:17.400 same as if you live in a city. All right, 0:09:17.440 --> 0:09:19.680 So let's say let's let's let's take the city as 0:09:19.720 --> 0:09:22.600 a kind of a metaphor here. We're gonna look at 0:09:22.600 --> 0:09:25.000 the city as an analog to the internet. It's not 0:09:25.679 --> 0:09:29.000 it's not entirely analogous, but we're going to kind of 0:09:29.200 --> 0:09:31.600 make some jumps here. So let's say you live in 0:09:31.640 --> 0:09:33.800 a city and the city tends to have a lot 0:09:33.880 --> 0:09:37.679 of traffic in it, and you may be at your 0:09:37.720 --> 0:09:39.600 house and you want to go eat at a popular 0:09:39.640 --> 0:09:43.760 restaurant that's across town. And so you know three different 0:09:43.800 --> 0:09:46.920 ways of getting to the place across town. One of 0:09:46.920 --> 0:09:49.520 them takes the least number of turns. It's it's the 0:09:49.559 --> 0:09:53.080 most direct route, but it's also the most heavily traffic route. 0:09:53.600 --> 0:09:56.240 So in other words, you could go that way and 0:09:56.360 --> 0:09:59.200 you wouldn't have to turn as frequently, but because of 0:09:59.240 --> 0:10:02.520 the the number of cars on that route, it will 0:10:02.559 --> 0:10:04.360 actually take you longer to get there than if you 0:10:04.400 --> 0:10:07.960 took a slightly more circuitous route that would have less 0:10:08.040 --> 0:10:09.960 traffic on it. So in that case, you say, you 0:10:09.960 --> 0:10:12.440 know what, I know that this is the direct path, 0:10:12.559 --> 0:10:14.040 but I'm going to take this more out of the 0:10:14.040 --> 0:10:17.400 way path. This it's it's a shortcut in time, but 0:10:17.520 --> 0:10:20.040 not in distance. And the same thing is true on 0:10:20.040 --> 0:10:22.280 the internet. You might be able to find a route 0:10:22.320 --> 0:10:26.080 to push traffic through that's going to be faster, even 0:10:26.120 --> 0:10:29.120 though it's not as direct. By the way, if you 0:10:29.160 --> 0:10:31.600 happen to live in Los Angeles, I understand that this 0:10:31.640 --> 0:10:34.880 is a sport that in Los Angeles, if you have 0:10:34.920 --> 0:10:36.960 a group of people and you have all decided to 0:10:37.000 --> 0:10:40.719 go someplace, the first hour of your travel time will 0:10:40.720 --> 0:10:43.760 actually be taken up spending time talking about the best 0:10:43.800 --> 0:10:47.640 way to get to where you're going. Okay, yeah, very 0:10:47.640 --> 0:10:51.280 little driving in LA so well that's it's. What's required 0:10:51.320 --> 0:10:54.000 is that you and at least one other person each 0:10:54.120 --> 0:10:56.560 in their own vehicles, have to be going to a 0:10:56.720 --> 0:11:00.240 specific place, leaving from the same location. And at that 0:11:00.320 --> 0:11:03.720 point you have launched into the game where then you 0:11:03.760 --> 0:11:05.400 say no, no, no, you don't want to do that. 0:11:05.400 --> 0:11:06.880 That's going to take you on the four oh five 0:11:07.080 --> 0:11:10.600 And haven't you heard of Carmageddon? And um so, yeah, 0:11:10.720 --> 0:11:12.960 it's the same sort of thing. Now. Granted, if if 0:11:13.040 --> 0:11:16.480 the city were empty, then the direct route would be 0:11:16.520 --> 0:11:19.599 the shortest, but the city is never empty because the 0:11:19.720 --> 0:11:23.440 zombie apocalypse hasn't happened yet, at least at the time 0:11:23.480 --> 0:11:27.080 of the recording of this podcast. Yes so, and by 0:11:27.120 --> 0:11:30.320 the way, if by the zombie apocalypse has happened since 0:11:30.320 --> 0:11:32.400 we record this podcast, I would like to have a 0:11:32.400 --> 0:11:35.320 shout out to all of our new listeners with BRAT. 0:11:37.400 --> 0:11:41.880 We're great with the zombie demographic. Oh I'm a little 0:11:41.880 --> 0:11:45.200 loopy today, Yeah you know, I hadn't noticed. Yeah, so anyway, 0:11:45.240 --> 0:11:48.640 The routing table is this list of essentially rules that 0:11:48.679 --> 0:11:52.400 the router follows in order to send packets across the network. 0:11:52.400 --> 0:11:56.520 And you might say, well, that seems pretty um stiff 0:11:56.640 --> 0:12:00.120 and and and inflexible. What happens when things change, Well, 0:12:00.440 --> 0:12:04.160 routing tables are not static. They are dynamic. They change 0:12:04.640 --> 0:12:07.840 all the time. And what's happening is routers are actually 0:12:07.840 --> 0:12:12.560 communicating with each other across the Internet constantly updating this 0:12:12.679 --> 0:12:16.120 information and changing it so that the most uh, the 0:12:16.160 --> 0:12:21.680 most efficient route is constantly being adjusted. And they're doing 0:12:21.679 --> 0:12:25.000 this through various protocols. Routing Information Protocol or r I 0:12:25.080 --> 0:12:29.520 p RIP that would be the one of the common 0:12:29.600 --> 0:12:32.800 protocols used. Another one is the Open Shortest Path First 0:12:32.960 --> 0:12:38.480 or OSPF protocol. These protocols are what routers use in 0:12:38.600 --> 0:12:41.640 order to update these routing tables so that data will 0:12:41.640 --> 0:12:45.280 co go across the network, across the Internet in the 0:12:45.320 --> 0:12:49.120 most efficient way possible, the way that's got the best 0:12:49.120 --> 0:12:51.200 guarantee that your information is going to get to where 0:12:51.200 --> 0:12:54.760 it needs to be. And each packet that Chris was 0:12:54.760 --> 0:12:57.680 talking about earlier has data in it that allows it 0:12:57.760 --> 0:13:02.559 to um well, allows it to the system to keep 0:13:02.600 --> 0:13:04.560 track of it. So let's say that you've sent a 0:13:04.600 --> 0:13:06.960 file like let's say I'm sending a file to Chris 0:13:07.200 --> 0:13:09.400 and Chris is on one network and I'm on another network, 0:13:10.240 --> 0:13:13.480 and uh, some of my packets don't get through. Well, 0:13:13.520 --> 0:13:16.679 the system keeps track of that. The what will happen 0:13:16.720 --> 0:13:18.920 is the information will come back to my computer and 0:13:18.960 --> 0:13:23.440 it will say, hey, packets three, seven, and twelve out 0:13:23.480 --> 0:13:25.520 of the forty that you sent never made it to 0:13:25.600 --> 0:13:29.000 Chris's machine. Then my machine will automatically re send those 0:13:29.000 --> 0:13:33.360 packets so that they will hopefully get to Chris's machine. Now, granted, 0:13:33.400 --> 0:13:35.640 all this is happening at near the speed of light, 0:13:35.760 --> 0:13:39.520 so you don't really notice the delay unless something's really 0:13:39.559 --> 0:13:43.000 really bad has happened. Um. And so this is all 0:13:43.040 --> 0:13:45.640 happening in the blink of an eye, but it's happening 0:13:45.640 --> 0:13:51.559 over and over and over across the Internet, right, um 0:13:51.640 --> 0:13:53.880 and and yes it's um just to go back to 0:13:53.880 --> 0:13:57.920 protocols to the protocols are basically, uh, languages that the 0:13:58.000 --> 0:14:01.480 routers used to speak to one another. Um. It's it 0:14:01.600 --> 0:14:06.880 enables people multiple manufacturers to make devices that will communicate 0:14:06.920 --> 0:14:10.120 with one another and be interoperable, which is you know, 0:14:10.600 --> 0:14:13.920 we talked about that actually on our podcast about how 0:14:14.160 --> 0:14:16.440 the Internet works, and we mentioned on some of the others. 0:14:16.440 --> 0:14:19.280 I think we probably did on IPv six that, uh, 0:14:19.320 --> 0:14:21.720 there are certain protocols that allow MC to talk to 0:14:21.800 --> 0:14:23.920 a Linux box and the Linux box to talk to 0:14:23.960 --> 0:14:26.600 a PC and etcetera. Right, they're all they're all using 0:14:26.640 --> 0:14:32.880 the computer equivalent of Esperanto. Yes, no, anyway, Yeah, that's 0:14:32.920 --> 0:14:35.560 that's what that's what our protocol is. And route routers 0:14:35.600 --> 0:14:38.520 do have those, uh, protocols that are specific to routers, 0:14:38.520 --> 0:14:40.600 and that that does help them balance the load somewhat 0:14:40.640 --> 0:14:42.680 on the Internet. Yeah, we should should say, I guess 0:14:42.680 --> 0:14:45.440 that a router really is a very specific computer. It's 0:14:45.440 --> 0:14:47.280 not just this box that you buy and you know 0:14:47.280 --> 0:14:49.240 it's got lights on it and when it's lit up, 0:14:49.240 --> 0:14:51.320 you know that the information is going through it is 0:14:51.400 --> 0:14:55.920 actually a very specific type of computer. Yeah, very specialized device. 0:14:55.960 --> 0:14:57.480 And and a lot of the routers, like the home 0:14:57.560 --> 0:15:00.200 routers that you purchase for your your home network, whether 0:15:00.240 --> 0:15:03.760 it's wireless or wired, also tend to act as a switch. 0:15:04.240 --> 0:15:06.640 And what by by that, I mean that it allows 0:15:06.680 --> 0:15:10.440 you to have your computers talk to one another. So 0:15:10.480 --> 0:15:13.040 if you have multiple computers at your house, you can 0:15:13.040 --> 0:15:15.880 send files from one machine to another machine without having 0:15:15.920 --> 0:15:18.040 to set up like some weird email thing or whatever, 0:15:18.080 --> 0:15:20.400 you can actually send it directly through your home network 0:15:20.680 --> 0:15:23.280 because your router also can be a switch. It's not 0:15:23.400 --> 0:15:27.040 just a router that sends information from your network to 0:15:27.120 --> 0:15:30.720 the Internet and back. Um. Also, when we were talking 0:15:30.760 --> 0:15:33.960 about information going across the network and figuring out the 0:15:33.960 --> 0:15:37.280 most efficient way, in the sense of routers, what they 0:15:37.960 --> 0:15:43.440 do is they calculate the cost of a of any 0:15:43.520 --> 0:15:47.960 particular data transmission, and cost does not mean dollars. It 0:15:48.000 --> 0:15:52.360 means hops, alright, So when a router sends information across 0:15:52.400 --> 0:15:55.200 the network, information may go from one router to another 0:15:55.280 --> 0:15:57.720 router to another router until it finally gets to wherever 0:15:57.760 --> 0:16:01.280 it's going. All right, Each time that information goes from 0:16:01.320 --> 0:16:05.600 one route or to another, that's called a hop, right now. Protocols, 0:16:05.640 --> 0:16:09.600 certain protocols have a limited number of hops that are 0:16:09.680 --> 0:16:13.760 built into uh any sort of data transference, and that 0:16:13.800 --> 0:16:17.120 information is stored in the data packet. Okay, So it's 0:16:17.120 --> 0:16:20.400 almost like I'm passing a note in class, and the 0:16:20.560 --> 0:16:23.960 note can only pass through three other people before it 0:16:24.000 --> 0:16:26.240 gets to my destination. It's one of them, the teacher. 0:16:26.880 --> 0:16:31.920 The teacher accesses the the packet of information it gets discarded, 0:16:32.120 --> 0:16:35.880 which is very much like what happens on the internet. Actually, so, 0:16:35.880 --> 0:16:38.680 so let's say that again. But now we're talking about 0:16:38.680 --> 0:16:42.640 a classroom. So Chris is sitting across the class from 0:16:42.680 --> 0:16:45.160 from me. I'm on one side, he's on the other side. 0:16:45.440 --> 0:16:48.760 I want to pass him a note that says something like, uh, 0:16:48.880 --> 0:16:51.120 I don't know the didn't the teacher wear that same 0:16:51.160 --> 0:16:54.040 outfit yesterday? And so I'm trying to send the the 0:16:54.280 --> 0:16:57.440 note across the class and it can only pass through 0:16:57.520 --> 0:17:01.320 three other hands up before it hits Chris. If it 0:17:01.360 --> 0:17:04.480 passes through more than that, then whoever the fourth person 0:17:04.560 --> 0:17:07.040 is is like, this is not worthwhile and just tosses 0:17:07.080 --> 0:17:10.240 the note away. The same thing is happening with hop 0:17:10.320 --> 0:17:13.120 counts if I send a packet of information. If I'm 0:17:13.119 --> 0:17:16.000 sending a file to Chris and it's going across the Internet, 0:17:16.040 --> 0:17:18.399 there's a certain number of hops that packet will go 0:17:18.480 --> 0:17:21.600 through before it hits the maximum number of hop count. 0:17:21.760 --> 0:17:23.680 Now that does not mean that the packet just automatically 0:17:23.720 --> 0:17:26.119 gets thrown away. It means that the system says, you 0:17:26.160 --> 0:17:28.720 know what, this packet has gone through this kind of 0:17:28.840 --> 0:17:32.000 serpentine pathway in order to get to where it's going. 0:17:32.320 --> 0:17:35.199 It's not getting there efficiently. Chances are this packet has 0:17:35.280 --> 0:17:39.639 already made it to the destination through a fewer number 0:17:39.680 --> 0:17:41.679 of hops. So I'm just going to toss the packet 0:17:41.680 --> 0:17:46.240 aside because otherwise, because the Internet is a redundant system, 0:17:46.320 --> 0:17:49.040 and because it's meant to be robust, and it's meant 0:17:49.040 --> 0:17:52.160 to get a packet of information to the destination through 0:17:52.200 --> 0:17:56.440 whatever means possible within the parameters of the Internet. If 0:17:56.480 --> 0:18:00.280 you didn't have these sort of uh discards them is 0:18:00.280 --> 0:18:05.040 put into place, the Internet would become overrun with packets. Yeah, 0:18:05.080 --> 0:18:07.280 because you know, if I'm sending that file to Chris 0:18:07.320 --> 0:18:10.600 and there's these duplicate packets going across the network, what 0:18:10.760 --> 0:18:13.679 happens when one packet gets to the destination and the 0:18:13.680 --> 0:18:16.119 other packets are still out there trying to trying to 0:18:16.119 --> 0:18:18.560 get to the destination. You're starting to clog up the 0:18:18.600 --> 0:18:22.680 Internet with all of this data. So these these fail 0:18:22.760 --> 0:18:26.320 safes are in place in order to prevent the Internet 0:18:26.400 --> 0:18:30.199 from just bogging down with too much data. And they 0:18:30.200 --> 0:18:32.680 didn't have to buy a like a digital router and 0:18:32.760 --> 0:18:35.520 go in and yeah, we've got we've got the routers, 0:18:35.560 --> 0:18:39.480 but not the routers router routers. I had to call 0:18:39.560 --> 0:18:41.880 them once it was did not go well, No, it's 0:18:42.040 --> 0:18:45.800 never anyway. Um. So in order to make all this work, 0:18:45.920 --> 0:18:49.160 in addition to your router and your network, you also 0:18:49.200 --> 0:18:52.240 have to have an address, a unique address for each 0:18:52.240 --> 0:18:54.840 item on the network. And this we've talked about in 0:18:55.119 --> 0:18:58.119 the I p V four versus I p V six podcast. 0:18:59.200 --> 0:19:03.680 Ideally you would have every single device that connects to 0:19:03.680 --> 0:19:08.160 the Internet would have its own unique address, so that 0:19:08.640 --> 0:19:11.679 whenever I want to send something to another device or 0:19:11.760 --> 0:19:14.879 receive information from another device, it would always go to 0:19:14.960 --> 0:19:17.680 the same address. And that way, it's just it's just efficient. 0:19:17.720 --> 0:19:21.040 It's a clean, efficient system. But we don't have enough 0:19:21.160 --> 0:19:25.560 addresses to do that, right. But each item and you 0:19:25.600 --> 0:19:27.640 may have actually seen this when you're going into your 0:19:28.040 --> 0:19:31.800 computer or you know, other devices like tablets and smartphones 0:19:31.800 --> 0:19:36.120 that use Internet networks, or video game systems, video game systems, uh, 0:19:36.200 --> 0:19:39.679 set top boxes, TVs. There's a lot of different devices 0:19:39.720 --> 0:19:42.480 that do it now, which is again part of the problem. Yeah, 0:19:42.520 --> 0:19:45.000 that this is called a MAC address. It's known as 0:19:45.240 --> 0:19:49.440 Media Access control and it doesn't look like well, actually, 0:19:49.560 --> 0:19:53.240 it kind of resembles an IP address because it has 0:19:53.240 --> 0:19:57.760 a series of letters and numbers separated by by colon's 0:19:58.480 --> 0:20:00.920 and that this is how you can identify I. Um, 0:20:00.960 --> 0:20:04.520 you know, say you have been foolish and have left 0:20:04.600 --> 0:20:11.160 your wireless network open to the public, and you have 0:20:11.400 --> 0:20:15.359 let's say a computer and a tablet and wait a minute, 0:20:15.359 --> 0:20:19.359 there are three things on your network. Well, then you 0:20:19.359 --> 0:20:21.800 can look at the MAC address on your computer, and 0:20:21.800 --> 0:20:23.480 you can look at the MAC address and your tablet 0:20:24.280 --> 0:20:27.760 and UH by process of elimination, figure out what the 0:20:27.800 --> 0:20:31.800 other device is and maybe even get an idea. If 0:20:31.840 --> 0:20:37.879 you can access the uh um the routers information page, 0:20:37.920 --> 0:20:40.399 you can you can see what what's going on, how 0:20:40.480 --> 0:20:43.359 much traffic it's using, and hopefully shut it down. You 0:20:43.359 --> 0:20:46.639 can even on on some uh probably on most of them, 0:20:46.680 --> 0:20:49.960 I would guess. I just don't want to be absolute um, 0:20:50.000 --> 0:20:52.880 you know, restricted to certain Mac addresses, so you can 0:20:52.960 --> 0:20:55.159 you can actually add you can on mind on the 0:20:56.119 --> 0:20:58.960 device I have at home. You can say, you know, 0:20:59.040 --> 0:21:02.679 I'm adding this tablet, I'm adding this game console, I'm 0:21:02.720 --> 0:21:06.879 adding this uh smartphone, I actually use WiFi calling on 0:21:06.920 --> 0:21:09.280 my smartphone, you know, and things like that, and say, okay, 0:21:09.440 --> 0:21:13.200 I'm only allowing MAC addresses that I know to join 0:21:13.280 --> 0:21:17.160 this network. But Basically, this is a way for um, 0:21:17.200 --> 0:21:20.840 you know, local networks to identify the devices and send 0:21:20.960 --> 0:21:22.960 the packets that go to that device, so they know, 0:21:23.480 --> 0:21:26.080 um that if you are reading how Stuff Works dot 0:21:26.080 --> 0:21:31.840 Com and your spouse is looking at a news network 0:21:32.359 --> 0:21:34.359 and you know you don't get the packets mixed up. 0:21:34.359 --> 0:21:36.440 It says, oh, well, these belong to this address, these 0:21:36.480 --> 0:21:38.320 belong to that address, and I'm going to be the 0:21:38.320 --> 0:21:42.440 traffic cop and send the right packets to the right place, right. Yeah. 0:21:42.440 --> 0:21:45.440 This this kind of ties into network address translation, which 0:21:45.440 --> 0:21:47.960 I referred to at the beginning of the podcast. We've 0:21:47.960 --> 0:21:49.800 also talked about that in the I p V four 0:21:49.920 --> 0:21:51.760 versus I p V six. Yes, it's one of the 0:21:51.760 --> 0:21:54.960 ways to address the problem of having more devices in 0:21:55.000 --> 0:21:59.400 the world than we have available IP addresses for those 0:21:59.400 --> 0:22:03.119 devices to connect to the Internet. Now, for information to 0:22:03.119 --> 0:22:05.840 travel across the Internet, it means that you have to 0:22:05.920 --> 0:22:11.199 have an Internet Protocol address. This allows the information to 0:22:11.359 --> 0:22:14.760 travel across it allows it allows other computers to find you, 0:22:15.000 --> 0:22:18.640 and allows your computer to send information to other computers. Uh. 0:22:18.680 --> 0:22:20.720 Without the IP addresses, you of course would have no 0:22:20.800 --> 0:22:24.040 way of knowing how to get information from one machine 0:22:24.080 --> 0:22:26.680