05-31-2017 02:36 AM - edited 03-08-2019 10:47 AM
Hello,
I had this exam simulated question:
1.If you take the network 192.168.1.0/24 and create four subnets from it, what are the new subnet IDs?
Solved! Go to Solution.
05-31-2017 03:26 AM
Simple way to calculate it -
1 bit = 2 to the power 1 = 2 subnets
2 bits = 2 to the power 2 = 4 subnets
3 bits = 2 to the power 3 = 8 subnets
etc.
So you need to use 2 bits from the last octet which gives 4 subnets ie. -
128 64 32 16 8 4 2 1
0 0
0 1
1 0
1 1
which gives you the following subnets -
192.168.1.0
192.168.1.64
192.168.1.128
192.168.1.192
Jon
05-31-2017 02:43 AM
The increment is 64.
You have calculated to get 4 you need 3 bits but you don't you only need 2 bits to give 4 different values which makes your subnet mask 255.255.255.192 ie. the first two bits in the last octet are being used.
Jon
05-31-2017 02:51 AM
Hello Jon,
Can you explain it to me how it works exactly?
I was always thought to calculate the subnet range based on how manny subnets i need.
128 64 32 16 8 4 2 1
1 0 0
i have 4= 3
Class c = 11111111.11111111.11111111.11100000
32
so shouldn`t the range be 192.168.1.0 -31
32- 63
64-95
96-127 ?
05-31-2017 03:26 AM
Simple way to calculate it -
1 bit = 2 to the power 1 = 2 subnets
2 bits = 2 to the power 2 = 4 subnets
3 bits = 2 to the power 3 = 8 subnets
etc.
So you need to use 2 bits from the last octet which gives 4 subnets ie. -
128 64 32 16 8 4 2 1
0 0
0 1
1 0
1 1
which gives you the following subnets -
192.168.1.0
192.168.1.64
192.168.1.128
192.168.1.192
Jon
05-31-2017 03:26 AM
Thank you John, from now on i will use the 2 to the power of something to determine the needed bits to make a number.
05-31-2017 04:25 AM
No problem, glad to have helped.
Jon
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