Divide the subnet, ask to tell how, how to divide the subnet

To do subnet division, we must first know 2 formulas, one is to divide the number of subnets = 2 to the nth power in equal quantities, where n is the number of subnet network number bits divided, and the other is the nth power of the number of hosts that the subnet accommodates = 2 minus 2, where n is the number of bits of the subnet host number after division, and minus 2 is because all 0 (subnet network address) and all 1 (subnet broadcast address) of the subnet host number are removed.

In addition, some old-fashioned books and textbook formulas also have to subtract 2, because at that time all 1 and all 0 subnets were not supported, and now they are supported, and generally do not need to subtract 2, and the things that have been eliminated are still turned out. Now that you've turned it out, you're going to be old.

Divide 6 subnets, to apply the old formula, 2 3-2 = 6, so the subnet number needs 3 digits, then the host number is 5 digits, the number of hosts in each subnet is 2 5-2 = 30, and the subnet mask:

Divided into: Network address, broadcast address.

Network address, broadcast address.

Network address, broadcast address.

Network address, broadcast address.

Network address, broadcast address.

Network address, broadcast address.

If the CIDR block is divided into 6 subnets.

1. The subnet mask is. Strictly speaking, this mask is divided into 8 subnets, because the average partition cannot divide 6 subnets.

33--62；65--94...Add 32 to each paragraph, and so on.

As above, add 32

Main CIDR Block:

Divide subnet one:

The host bits of the CIDR block to which subnet 1 belongs are all 0).

The broadcast bit of the subnet is the host bit, and all bits are 1).

Therefore, the IP range of Subnet 1 is:

Divide subnet two:

The host bits of the CIDR block to which Subnet 2 belongs are all 0).

The second broadcast bit of the subnet is the host bit, and all bits are 1).

Therefore, the IP range of subnet 2 is:

Divide subnet three:

The host bits of the CIDR block to which Subnet 3 belongs are all 0).

The three broadcast bits of the subnet are all 1) of the host bits

Therefore, the IP range of subnet 3 is:

Divide subnet four:

The host bits of the CIDR block to which subnet four belong are all 0).

The four broadcast bits of the subnet are all hosts, and all bits are 1).

So the IP range of subnet four is:

Thinking of the following four situations, it is easy to understand!

If the network number is, it is necessary to divide it into 3 subnets (according to specific requirements).

For example, if you know that you want to divide three subnets, it is easy to know that you need to borrow three subnets from the host number to act as subnet numbers. The subnet number part can form six permutations. The following IP range can be obtained.

Subnet number (two pants big suspect base system representation).

IP address range (dotted decimal imitation Bi system).

Where: for.

The subnet number is determined as follows:

This is the range of hosts with subnet number 001. So the range of the number of hosts is as follows:

Note: 1. The subnet number cannot be all 0 or 1. So it has to be a permutation of .

2. The host bit cannot be all 1 or all 0, which is why 63 and 254 are taken instead of 64 and 255.

3. Note that the subnet number that is borrowed is the first three digits of the host.

The same goes for the other 5 types. (Corrections are welcome, thank you).