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These are the user uploaded subtitles that are being translated: 1 00:00:02,210 --> 00:00:08,120 It all the job is also is to segment the data. 2 00:00:11,770 --> 00:00:22,290 It uses sequence numbers to do this and it also has an interesting thing to use between communication 3 00:00:22,500 --> 00:00:23,910 which is call port numbers 4 00:00:28,900 --> 00:00:40,580 that each one of these things has its own lesson to teach this means if the traffic is going to not 5 00:00:40,580 --> 00:00:45,710 be guaranteed it means I'm going to send the traffic down the wire and I don't really care if it gets 6 00:00:45,710 --> 00:00:46,810 there or not it's best. 7 00:00:46,850 --> 00:00:50,260 I mean I wanted to get there but I'm not going to make sure it does get there. 8 00:00:51,360 --> 00:01:00,600 TZP is a mess that is a method of being guarantying traffic and making sure that my traffic is being 9 00:01:00,600 --> 00:01:01,460 used. 10 00:01:01,660 --> 00:01:12,200 B I'm sorry being delivered and in order for me to get that guarantee guess what I'm going to use secret 11 00:01:12,200 --> 00:01:18,850 numbers to make sure that I'm getting the proper data back. 12 00:01:20,880 --> 00:01:23,910 And make sure the my date has been set let's see how that works so quick 13 00:01:32,260 --> 00:01:41,500 if I see a piece of data over the PC one now remember sequence numbers in TCAP or you know TCAP uses 14 00:01:41,490 --> 00:01:47,300 secret numbers to make sure we have guaranteed communication which means using TCAP you are expecting 15 00:01:47,300 --> 00:01:49,310 reliable transmission a transmission 16 00:01:53,450 --> 00:02:01,020 between poverty's buffer these devices p.s. one since the date over here is my data comes out here. 17 00:02:01,020 --> 00:02:09,690 PC to attached to this data up have a sequence of say seekers number one piece or two will come back 18 00:02:09,690 --> 00:02:14,230 and say look I have this data I got it. 19 00:02:14,310 --> 00:02:16,870 This is going to send what is called Room knowledge meant. 20 00:02:17,070 --> 00:02:25,380 And with that acknowledgement he's going to send a sequence number of to that sequence number two means 21 00:02:25,380 --> 00:02:32,400 to receive that piece of that demeans the PC one PC one gets this acknowledgment with the sequence number 22 00:02:32,420 --> 00:02:33,220 two. 23 00:02:33,630 --> 00:02:41,230 He knows pc 2 is expecting sequence number of two if PC to send this announcement back with a sequence 24 00:02:41,230 --> 00:02:46,990 number of one it's tell the pc that he's expecting a sequel number of one. 25 00:02:47,180 --> 00:02:56,180 And P.S. one knows that both of your spectrum 1 and already set one I need to resend one because you're 26 00:02:56,180 --> 00:02:56,970 not getting it. 27 00:02:58,120 --> 00:03:04,990 So I'll go ahead and send that and these sequent numbers of which used to guarantee those traffic back 28 00:03:04,990 --> 00:03:05,650 and forth. 29 00:03:05,680 --> 00:03:07,020 That's just the basics. 30 00:03:08,380 --> 00:03:10,750 We'll get a little bit more detail into it later on. 31 00:03:12,190 --> 00:03:22,580 Point numbers think of port numbers as a means of listening on a particular gateway Nasik gateway I'm 32 00:03:22,580 --> 00:03:31,340 talking Mollah hyperspace gateway not a gateway and networking think of them as what you can think of 33 00:03:31,340 --> 00:03:32,190 those tunnels. 34 00:03:32,270 --> 00:03:37,010 But then we have tunnel interfaces that may confuse you think of you actually going through a wormhole 35 00:03:37,040 --> 00:03:37,990 in space. 36 00:03:39,950 --> 00:03:44,690 If this PC want to sit in here 37 00:03:51,510 --> 00:03:58,380 and I'm trying to send data over to PC to and I want to send an out port number 23 38 00:04:02,090 --> 00:04:03,470 I'm going as soon as data 39 00:04:06,980 --> 00:04:13,480 through this nice little warm hole bending space and time excels are right. 40 00:04:17,380 --> 00:04:24,330 Going down port 23 over to this PC Now that's one way of looking at it. 41 00:04:24,770 --> 00:04:27,460 But then some people get confused with that as well. 42 00:04:28,150 --> 00:04:32,350 Because they think that this is 23 is automatically open and so on and so on. 43 00:04:32,620 --> 00:04:39,930 So let's think of it as another way I like explained it that way because a lot of people read it as 44 00:04:39,930 --> 00:04:42,970 as a warm hole and it kind of get kind of confused. 45 00:04:43,220 --> 00:04:48,200 I like to think of them also as this wall 46 00:04:51,480 --> 00:04:52,390 of Doris 47 00:04:56,520 --> 00:04:57,830 sitting on the PC 48 00:05:03,270 --> 00:05:05,060 and we've got lots of doors. 49 00:05:05,160 --> 00:05:08,730 OK here's our door handle for each one of these doors. 50 00:05:10,670 --> 00:05:11,720 Imagine 51 00:05:18,200 --> 00:05:20,340 that these doors have numbers on them. 52 00:05:21,450 --> 00:05:23,800 Now pc 2 is going to be listening 53 00:05:26,300 --> 00:05:29,770 and each one of these doors he's going to have his ear up to them. 54 00:05:29,960 --> 00:05:36,070 PC to just define what port number is or what doors he's allowed to listen on. 55 00:05:37,270 --> 00:05:50,650 So PC to say I'm going to listen on door 23 Orndorff 15 and on door 33 OK. 56 00:05:51,360 --> 00:05:57,120 So these are the only doors and I'm going to be listening on and that's it. 57 00:05:57,120 --> 00:06:05,630 So if PC one sends information over the PC to and he says I'm going to send this information to port 58 00:06:06,630 --> 00:06:17,570 25 and PC too is not listening on the port 25 you'll never be able to open one of these doors. 59 00:06:17,620 --> 00:06:20,730 He's not he's not going to open the door for traffic to come through. 60 00:06:21,250 --> 00:06:27,000 And in fact PC is going to say I'm not listening on 25 CJA and I'll drop the data. 61 00:06:30,110 --> 00:06:37,490 So these these so-called port numbers these doors PC to needs to be listening on that port number in 62 00:06:37,490 --> 00:06:39,380 order to allow the traffic to go in. 63 00:06:39,380 --> 00:06:47,270 Now if I communicate on port 23 when that's beautiful that's fantastic 64 00:06:52,260 --> 00:06:55,590 PC two will actually allow that traffic to come in. 65 00:06:55,680 --> 00:07:01,740 Open this door because he's listening on 23 and that traffic will be allowed to come in. 66 00:07:05,080 --> 00:07:14,050 This is the transport's job to make sure of this transformation so let's look at it like this 67 00:07:19,980 --> 00:07:26,730 I'm going to have my application Ababil my application and application I'm going to say I want this 68 00:07:26,730 --> 00:07:37,770 application to be Portland OR 1 1 1 1 1111 So what's going to happen is when ever this pc will say PC 69 00:07:37,810 --> 00:07:48,140 one is using this application in that PC goes it's building these layers of presentation layer session 70 00:07:48,140 --> 00:07:53,750 layer session layer remembered as such a layer actually goes out and tries to create the session once 71 00:07:53,750 --> 00:07:55,010 the session is created. 72 00:07:55,010 --> 00:08:00,290 Now we're going to get to the transport layer the transport layer is going to define whether it's going 73 00:08:00,290 --> 00:08:01,680 to be UDP or TZP 74 00:08:04,280 --> 00:08:08,690 ever GTP who cares it's just going to send it out with the port number and be done with it. 75 00:08:08,870 --> 00:08:15,650 If it's TZP we're going to set up a TCAP session first to to make sure we have this guarantee. 76 00:08:15,660 --> 00:08:27,020 Traffic communication going and once we get that TCAP session set up every time I go through and communicate 77 00:08:28,730 --> 00:08:35,190 to the other PC it's going to be with Pt. 1 1 1 1 that door 78 00:08:38,120 --> 00:08:45,590 so this is nice because if I have a PC sitting here you see one gone into this switch 79 00:08:49,350 --> 00:08:53,340 P.S. to receive three 80 00:08:58,270 --> 00:09:03,190 have a server sitting here this server could be listening 81 00:09:06,700 --> 00:09:11,020 on port 1111 and these PCs are not. 82 00:09:11,380 --> 00:09:17,700 So that's nice because I know if my traffic accidentally gets too PC to a PC 3 who cares. 83 00:09:17,910 --> 00:09:19,200 They're not listening on port. 84 00:09:19,200 --> 00:09:21,780 One one thousand one hundred eleven. 85 00:09:21,850 --> 00:09:23,030 So who cares. 86 00:09:24,810 --> 00:09:31,880 Two and Three would drop it and as long as the server gets it he guessed or ill allow the traffic to 87 00:09:31,880 --> 00:09:32,380 go through. 88 00:09:32,420 --> 00:09:35,340 Listening to the old read the traffic see what it's for. 89 00:09:35,540 --> 00:09:38,900 Whatever request that server has he will send it back out. 90 00:09:42,220 --> 00:09:43,170 Now this is pretty cool. 91 00:09:43,180 --> 00:09:50,250 Remember this is the basics we're going to get to get more detail later on so if it's not making all 92 00:09:50,250 --> 00:09:51,550 sense to you that's fine. 93 00:09:51,750 --> 00:09:59,530 For right now so the application will define whether he wants to do UDP traffic and TCAP traffic. 94 00:09:59,810 --> 00:10:04,080 And so I'm talking about the dual layer as worked with each other because the application would definitely 95 00:10:04,110 --> 00:10:08,970 tell the presentation how you know how it needs to be presented and a presentation to make sure that 96 00:10:08,970 --> 00:10:17,100 that happens the presentation will work with the session to make sure that the sessions up 97 00:10:20,240 --> 00:10:22,030 I want to see them work together. 98 00:10:22,120 --> 00:10:25,060 Really the presentation is really working with the application 99 00:10:27,620 --> 00:10:34,820 technically it's really working at the presentation after this part has been defined the session will 100 00:10:34,820 --> 00:10:40,130 start to be created through the transport system a kind of working together because the session is 10845