1 00:00:00,079 --> 00:00:06,062 In the previous video, we already done doing subnetting calculation with different case. 2 00:00:06,763 --> 00:00:15,206 Next in this video, we are going to learn about the concept of block subnet. In the previous video, 3 00:00:15,206 --> 00:00:22,834 I said that block subnet is just like a room. This is the result of our calculation before. 4 00:00:23,227 --> 00:00:33,901 Here we have block subnet 1, 2, 3 and so on. We can imagine that each block subnet is used in each room . 5 00:00:34,356 --> 00:00:41,839 Let’s say we have a building and in the building we have room 1, 2 and 3. 6 00:00:42,221 --> 00:00:46,813 So we can use the first block subnet for room number 1, 7 00:00:47,034 --> 00:00:53,409 second block subnet for room number 2, and third block subnet for room number 3. 8 00:00:54,086 --> 00:01:02,646 Let’s say in the room number 1 there are 15 pc, room number 2 also has 15 pc, and room number 9 00:01:02,646 --> 00:01:11,840 3 also has 15 pc. 15 pc in the room number 1 can use ip range from first block subnet, 10 00:01:12,431 --> 00:01:18,000 15 pc in the room number 2 can use ip range from second block subnet, 11 00:01:18,535 --> 00:01:25,446 and finally 15 pc in the room number 3 can use ip range from the third block subnet. 12 00:01:25,975 --> 00:01:31,514 One thing that you need to remember is that by default, each block subnet can't 13 00:01:31,514 --> 00:01:43,058 communicate each others. So let’s say here we have PC 1 and PC 2. The ip address of PC 1 is 10.10.10.10 14 00:01:43,403 --> 00:01:50,115 and the ip address of PC 2 is 10.10.10.20/27. 15 00:01:51,739 --> 00:01:58,328 In this case, PC 1 and PC 2 can communicate each others, why? 16 00:01:58,586 --> 00:02:05,452 Because these 2 pc is in the same block subnet. Which is first block subnet. 17 00:02:05,655 --> 00:02:12,831 Here we can see that 10 is in the first block subnet, and 20 also in the first block subnet. 18 00:02:13,255 --> 00:02:20,738 Okay, so PC 1 can communicate with PC 2 because they are in the same block subnet. 19 00:02:21,379 --> 00:02:32,117 But how if the ip address of PC 1 is 10.10.10.15/27, and the ip address of PC 2 is 20 00:02:32,117 --> 00:02:44,577 10.10.10.50/27? In this case, these 2 pc can not communicate each others. Why? 21 00:02:44,577 --> 00:02:51,680 Because PC 1 is in the first block subnet but PC 2 in the second block subnet. 22 00:02:52,942 --> 00:02:56,375 Okay let’s try it in the Cisco Packet Tracer. 23 00:02:57,000 --> 00:03:04,455 Here we will configure the ip address as our calculation before. We will use the first case first. 24 00:03:04,578 --> 00:03:19,452 The ip address of PC 1 is 10.10.10.10/27 and the ip address of PC 2 is 10.10.10.20/27. 25 00:03:20,308 --> 00:03:27,132 Okay let’s configure the ip address of PC 1. Go to dekstop, ip configuration, 26 00:03:27,508 --> 00:03:39,291 the ip address is 10.10.10.10, the subnetmask is 255.255.255.224. 27 00:03:39,680 --> 00:03:47,298 remember that this subnetmask is the result of our calculation before for prefix /27. 28 00:03:48,332 --> 00:03:57,791 Okay next, let’s configure the Ip address of PC 2. The ip address is 10.10.10.20, 29 00:03:58,043 --> 00:04:09,120 and the subnetmask is 255.255.255.224. close this, and open the command prompt. 30 00:04:09,674 --> 00:04:19,520 Here let’s try to ping to the PC 1. Which is 10.10.10.10, here we can see that the ping 31 00:04:19,520 --> 00:04:22,948 from PC 2 to PC 1 is successful. 32 00:04:23,526 --> 00:04:34,178 Next, let’s try the second case, so the ip address of PC 1 will be 10.10.10.15/27, 33 00:04:34,375 --> 00:04:47,865 and the ip address of PC 2 will be 10.10.10.50/27. Go to PC 1, here let’s change the ip address to 15. 34 00:04:48,160 --> 00:04:55,096 Next go to PC 2, and change this to 50. 35 00:04:55,932 --> 00:05:02,724 Now let’s ping to PC 1. Which is 10.10.10.15. 36 00:05:04,984 --> 00:05:15,218 Okay here we can see that the result is request timeout. This is means that PC 2 and PC 1 can not communicate each others. 37 00:05:16,197 --> 00:05:22,849 Okay I hope you now understand the concept of block subnet. Remember that by default 38 00:05:22,849 --> 00:05:29,458 each block subnet can not communicate each others. But some of you may be have a question, 39 00:05:29,865 --> 00:05:36,142 how if we want to each block subnet can communicate each others? For that case, 40 00:05:36,142 --> 00:05:43,378 we will need additional device, which is router. We will learn about router in the next video. 41 00:05:44,339 --> 00:05:50,757 Okay I think enough for this video. Thankyou for watching and see you on the next video.