WEBVTT 00:05.190 --> 00:10.050 So guys, let us see the demonstration of Dhcp server with multiplexing. 00:10.620 --> 00:17.700 So the Dhcp server with multiplexing capability has been implemented in the file TCP server dot c. 00:18.720 --> 00:21.150 So we will compile this file. 00:28.100 --> 00:33.950 So the compilation process will create an executable called X underscore server. 00:33.980 --> 00:37.520 You just have to run this binary. 00:38.240 --> 00:45.350 So our TCP server with multiplexing has started and it has created the master socket file descriptor 00:45.350 --> 00:48.110 and is now blocked on the select system call. 00:48.830 --> 00:54.290 That is, it is now waiting for the connection initiation request from some client. 00:56.050 --> 01:00.130 And now in the second window, you can see that we have a TCP client. 01:00.160 --> 01:06.820 We have already discussed the implementation of TCP client and we need not do any changes in the TCP 01:06.820 --> 01:07.870 client program. 01:07.870 --> 01:12.050 It will continue to be exactly same as what we discussed. 01:12.070 --> 01:18.790 So I can simply run the binary of TCP client that is the executable of TCP client program. 01:18.790 --> 01:25.780 And you can see that the moment I start the TCP client program, the TCP client sends the connection 01:25.780 --> 01:28.440 initiation request to the TCP server. 01:28.450 --> 01:35.350 The server has accepted the connection request from the client and is again blocked on the select system 01:35.350 --> 01:35.920 call. 01:36.460 --> 01:43.900 And now it is either waiting for the data request from the connected client that is this client or it 01:43.900 --> 01:48.280 can also receives the connection initiation request from some new client. 01:48.610 --> 01:54.950 So let us say that the connected client sends some data to our TCP server. 01:54.970 --> 01:57.740 Let us say it sends 10 or 20. 01:57.770 --> 02:04.550 So you can see that your TCP client receives the response back from the server, right? 02:04.550 --> 02:11.120 And your client is still connected with the TCP server and it can still carry out more data exchange 02:11.120 --> 02:12.140 with the server. 02:12.530 --> 02:19.130 Now let us say at this point of time a new client comes and it sends connection initiation request to 02:19.130 --> 02:19.880 the server. 02:20.450 --> 02:23.960 So let me start a new client program in the another window. 02:29.170 --> 02:37.060 So I'm starting a new client program in another window, and you can see the moment I execute this, 02:38.170 --> 02:42.320 the new TCP client sends the connection initiation request to the server. 02:42.340 --> 02:47.650 So at this point of time, two clients are connected to our TCP server. 02:50.100 --> 02:50.700 Right. 02:50.700 --> 02:57.120 And now let's see if our TCP server can process the data request from the second client or not. 02:57.510 --> 03:03.180 So let's say the second client sends the value 20 and 30 to the TCP server. 03:03.360 --> 03:10.500 Oh, you can see that our TCP server has processed the data and sends the result back to the second 03:10.500 --> 03:11.160 client. 03:11.460 --> 03:18.220 Now let's see that whether our first client can still communicate with our TCP server or not. 03:18.240 --> 03:24.620 So let's say our client C1 that is the first client sends the data to the TCP server. 03:24.630 --> 03:33.810 Let's say it sends the value of A as nine and B as two, and it still receives the result. 03:34.560 --> 03:35.370 Right. 03:35.460 --> 03:41.520 And let's see if our second client can still communicate with the TCP server. 03:41.520 --> 03:48.150 So let us send the value of A and B as 90 and 30 and it is receiving the result. 03:48.550 --> 03:55.630 So you can see that both the clients are able to communicate with the TCP server and our TCP server 03:55.630 --> 04:03.550 is able to process the data request from the two connected clients and entertain our process those requests 04:03.550 --> 04:04.690 at the same time. 04:06.150 --> 04:06.720 Right. 04:06.720 --> 04:14.130 And while our TCP server is entertaining the connected clients, a new client can always come and join 04:14.130 --> 04:15.300 the communication. 04:17.230 --> 04:17.770 Right. 04:17.770 --> 04:25.930 So this is what TCP server with multiplexing is supposed to do and we see that our TCP server is doing 04:25.930 --> 04:28.570 its job fairly well. 04:30.090 --> 04:30.600 Right. 04:30.600 --> 04:37.770 So this is how a server should be designed, that it should be able to process the data request from 04:37.770 --> 04:45.210 multiple connected clients as well as it should be in a position to process the connection initiation 04:45.210 --> 04:47.760 request from the new client. 04:48.330 --> 04:55.050 So this was Dhcp server with multiplexing capabilities implementation details for you. 04:56.270 --> 05:00.800 So this is how TCP server with multiplexing are implemented. 05:02.530 --> 05:10.270 And also, one more thing that I would like to point out that we are learning the entire TCP or socket 05:10.270 --> 05:17.290 programming in C, and you can see that when you learn the stuff in C programming language, then you 05:17.290 --> 05:19.760 really know what exactly you are doing. 05:19.780 --> 05:24.310 You really do things at the lowest level of implementation. 05:24.340 --> 05:31.960 Had you use Java or Python in order to implement these Dhcp servers or in order to do the socket programming, 05:31.960 --> 05:40.570 you would have met the same result, but probably you will not be having the in-depth knowledge and 05:40.570 --> 05:48.040 you will not be knowing that what exactly goes behind the scenes when you implement such a complicated 05:48.040 --> 05:49.720 server logic. 05:50.320 --> 05:58.870 So this is the benefit of learning stuff in C programming language because C language is neither a very 05:58.870 --> 06:02.630 high level language nor it is a very low level language. 06:02.630 --> 06:10.250 And yet it is a very powerful language and often termed as the mother of all the languages.