0 1 00:00:00,960 --> 00:00:07,020 Like all protocols, HTTP involves a transfer of information between a client and a server. 1 2 00:00:07,320 --> 00:00:12,000 The client and server are two remote entities that wish to communicate with each other. 2 3 00:00:12,450 --> 00:00:15,960 The client makes request and the server answers. 3 4 00:00:16,380 --> 00:00:18,700 There are many types of client and server. 4 5 00:00:18,720 --> 00:00:23,640 For example, they are mail clients when we use POP and SMTP protocol. 5 6 00:00:23,820 --> 00:00:30,000 There are files client and server when we use FTP protocol and of course there are web client and server 6 7 00:00:30,000 --> 00:00:35,470 when we use HTTP protocols. In a client-server communication, 7 8 00:00:35,490 --> 00:00:40,050 it's very important to know who is the client and who is the server. 8 9 00:00:40,500 --> 00:00:48,600 In our case, we have two entities: the LoRaWAN server and the IoT platform, and depending on the situation, 9 10 00:00:48,600 --> 00:00:50,370 we'll have to assign a role: 10 11 00:00:50,370 --> 00:00:56,790 Sometimes the LoRaWAN Server will be the client and the IoT platform, the server, and sometimes it will be 11 12 00:00:56,790 --> 00:00:58,460 the other way around. 12 13 00:00:58,470 --> 00:01:02,370 The LoRaWAN Server will be the server and the IoT platform, the client. 13 14 00:01:03,540 --> 00:01:04,310 Great. 14 15 00:01:04,320 --> 00:01:11,580 So, I agree it's a little bit confusing because sometimes, the LoRaWAN Server can be the client, but 15 16 00:01:11,580 --> 00:01:16,950 the term "server" in LoRaWAN Server only means that it serves the LoRaWAN protocol. 16 17 00:01:17,250 --> 00:01:22,920 Once again here, we're not dealing with LoRaWAN anymore, but only with the transmission of the user 17 18 00:01:22,920 --> 00:01:24,960 payload to the IoT platform. 18 19 00:01:25,740 --> 00:01:31,470 OK, so each time we're going to deal with the dialogue between the LoRaWAN server on the IoT platform, 19 20 00:01:31,470 --> 00:01:36,870 we will represent the LoRaWAN server at the top and the IoT platform at the bottom. 20 21 00:01:37,560 --> 00:01:41,430 The LoRaWAN server can be any of the existing one. 21 22 00:01:41,430 --> 00:01:48,450 So, TTN, Actility, LORIOT, ChirpStack, or any others, it really doesn't matter. 22 23 00:01:48,840 --> 00:01:56,490 And at the bottom, the IoT platform can be the one we've built ourselves or any open sources or proprietary 23 24 00:01:56,490 --> 00:01:57,540 ones available. 24 25 00:01:58,050 --> 00:02:03,180 I'm not going to list the IoT platform available here, because there will be a specific chapter to build 25 26 00:02:03,180 --> 00:02:04,110 our own. 26 27 00:02:04,440 --> 00:02:10,260 Anyway, we now need to understand "who is requesting?" and "who is serving?" 27 28 00:02:10,470 --> 00:02:15,990 For our explanation, we'll again use the same application described in the video at the beginning of this 28 29 00:02:15,990 --> 00:02:16,560 lecture. 29 30 00:02:16,680 --> 00:02:18,780 Sometimes, we'll send the string 30 31 00:02:18,780 --> 00:02:19,560 "Hello". 31 32 00:02:19,650 --> 00:02:22,740 But for some other demonstration we'll send the temperature. 32 33 00:02:23,340 --> 00:02:29,610 And, when we'll deal with downlink, then we'll use the ability to turn an LED on or off. 33 34 00:02:29,790 --> 00:02:33,450 Of course, the command will be managed from the IoT platform. 34 35 00:02:33,570 --> 00:02:36,180 So, there are two situations to consider: 35 36 00:02:36,690 --> 00:02:44,190 - UpLink: when the "hello" string or the temperature comes from the end-device. And - Downlink: when a switch 36 37 00:02:44,190 --> 00:02:47,880 command comes from the user application on the IoT platform. 37 38 00:02:48,930 --> 00:02:54,060 So, now we'll see in the next video two flavors of the HTTP protocol. 38 39 00:02:54,570 --> 00:02:56,950 First, we can use the GET method. 39 40 00:02:56,970 --> 00:03:00,240 Then we'll see the POST method of the HTTP protocol. 40 41 00:03:00,600 --> 00:03:03,690 Let's start with the first method called HTTP GET.