hello and this is sunny welcome back today my topic is subnetting a subnet is a logical subdivision of IP network the process of dividing a network into two or more networks is called subnetting the main purpose of subnetting is to help relieve a network congestion and improve network performance security is another benefit of a subnet iam besides your network a professor may test you about subnetting Kampuchea national network plaza certification also expects you to know how to subnet however some textbooks make subnetting is very complicated and confusing in this video I will use a very simple way sunny way of subnetting and after this video you will find subnetting is not a difficult at all however in order to understand subnetting we do need some basic knowledge such as sadness mosque network ID host ID and a broadcast ID i put several videos links below just in case you needed them one more point this video is much longer than most of my other videos so please bear with me [Music] let's take a look at my example one day your supervisor walks to you seeing here's a network ID place it create three separate networks or subnets for coffee shop sunny cafe why is for the office why is for the front desk and storage room and one is for the public use your task is to list each service network ID subnet mask host ideal range the number of will useful host IDs and broadcast ID I put this example below this video so you can copy to your document for your reference as we discuss the process of subnetting first is first let's build a table this table is the most critical because once we build it we can easily solve most subnetting questions and this table has a three rows the first row is a subnet with nine numbers we start with 1 then 2 4 8 16 32 64 128 and 256 the pattern is each number is a double of is previous number okay the second row is a host this row tells the number were total host IDs for each new subnet start with 256 then 128 64 32 16 8 4 2 and one the pattern is each number is half of his previous number or the second row is the reverse order of the first row you see everyone can handle this right the third row is a subnet mask we use shorthand format starting with 24 25 26 27 28 29 30 31 32 well we are done I call this table sunny subnetting table or simply sunny table because is a simple sunny but a powerful table for subnetting and a subnetting subnet now we use a sonnet able to solve the subnetting example mission about let's go back to the question you are giving a network ID 100 mm 168 4.0 / 24/24 somnus mosque you are required to get three subnets three is the key keyword now look at the sunny table and it try to find the three subnets in the first or in the top row of course there is no exactly 3 semanas but for subnets are suitable because we can get 4 subnets and choose any three subnets for sunny cafe so we choose a full subnets for let me circle the whole column ignoring all other columns because we only use this three numbers and we can get all our answers just from this column or these three numbers for eighty-four and a slash 26:4 means four subnets sixty-four means each subnet each new subnet we are how was 64 total host ideas including network ID and a broadcast ID / 26 is the new subnet mask for all these four subnets [Music] well let's list all these four subnets information a network ID subnet mask host ID wrench the number we'll use for host IDs and broadcast ID let's find the first network ID the first network ID is always the original network ID which is 1 and E 2 tau 168 are 4.0 that's easy right I use read found to emphasize the last number because the first three numbers stay the same across the table so place just a focus on last number in red we will get next network ID by simply adding 64 to is previous network ID therefore the second network ID is 0 plus 64 which is a 64 the third network ID would be 64 + 64 which is 128 the fourth network ID is 128 plus 64 which is 192 now subnet mask for each subnet well they are all / 26 the original subnet mask is slash 24 we are done with a sub s mask column now let's list the number of a usable host IDs and we can also find an answer from the sunny table which is 64 64 is the total number of a host IDs for each Network or each subnet but the first host ID is reserved for network ID and alas the host ID is reserved for broadcast ID thus the number of useable host ID is 64 minus 2 which is a 62 thus we write down 62 for all 4 subnets we are done with the fourth column now let's look at at the broadcast ID for each subnet keep in mind the last host ID is reserved for his broadcast ID therefore broadcast ID for the first subnet is 63 and we can tell with the reference to the next network ID 64 next broadcast ID is 127 next one is 191 and that the last broadcast ID is 255 we can say the broadcast ID equals next subnet networks ID minus 1 we can also do like this once you know the first broadcast the ID 63 and then you can simply add 64 to get the second broadcast ID and the 63 plus 64 is 1 2 new semi and if they add 64 2 1 2 new semi which we get the third brother Casa ID 1 91 and then they increase by 64 again to get the fourth broadcast the ID which is 255 we are almost done one last column the host ID arrange a subnet host ID range is is any IDs between his network ID and a broadcast ID for the first subnet 1 262 is between network ID 0 and broadcast ID 63 the second host an ideal range 65 to 126 is between 64 and 127th the third host ID range 129 to 190 is between 128 and 191 the fourth host ID range is between 192 and a 255 which is 193 to 254 so to keep simple we only talked about it last a number and because the first of three numbers stay the same that's all we get all answers you can assign any 3 out of 4 subnets for sunny cafe 1 subnet is wasted of course that's the downsides of subnetting no biggie I want to thank you for following me at this point you are a very patient person for listening to me with my strong English accent even though the process sounds a tedious but once you get to know how to do it you can solve any similar questions in no time I put a 1 similar question below for your practice I also provided the answer below for your reference if you have a questions please feel free to leave your comments or ask me questions I would be happy to help you in next video I will go one step further subnetting a subnet using the same sunny table in same sunny way please stay tuned thank you very much and see you next time [Music]