Shulou(Shulou.com)06/01 Report--

Subnetting: dividing a large range of addresses into smaller ranges of addresses.

The role of subnetting: in order to make reasonable use of addresses, to save addresses and facilitate address management.

The minimum IP address is the network address and the maximum is the broadcast address.

For example, 192.168.1.0 is the network address and 192.168.1.255 is the broadcast address.

The IP address itself consists of a binary number system, so the IP address is converted to a decimal number system for ease of memory.

Subnetting rules:

V first determine how many bits to borrow and get the address field according to the possibility.

V converts the binary value to decimal to determine the network number. (network number equals network address)

V calculates the available address, which is equal to the current network number plus 1 to the next network number minus 2.

V calculates the mask.

Note: there are only two possibilities for binary numbers, either 1 or 0.

We usually subnet the last part of the address.

Converting the last part of 192.168.1.0 to a binary number is 192.168.1.00000000 (8 zeros)

Number of digits borrowed

The resulting address field

Convert to decimal network number

Available address

Mask

one

0 0000000

0

1-126

255.255.255.128

1 0000000

one hundred and twenty eight

129-254

255.255.255.128

two

00 000000

0

1-62

255.255.255.192

01 000000

sixty-four

65-126

255.255.255.192

10 000000

one hundred and twenty eight

129-190

255.255.255.192

11 000000

one hundred and ninety two

193-254

255.255.255.192

three

000 00000

0

1-30

255.255.255.224

001 00000

thirty-two

33-62

255.255.255.224

010 00000

sixty-four

65-94

255.255.255.224

011 00000

ninety-six

97-126

255.255.255.224

100 00000

one hundred and twenty eight

129-158

255.255.255.224

101 00000

one hundred and sixty

161-190

255.255.255.224

110 00000

one hundred and ninety two

193-222

255.255.255.224

111 00000

two hundred and twenty four

225-254

255.255.255.224

In turn.

In turn.

In turn.

In turn.

In turn.

Interpretation: two address fields can be obtained by 1 bit, four address fields can be obtained by 2 bits, and eight address segments can be obtained by 4 bits, in turn.

Available address calculation: the resulting network number plus 1 to the next network number minus 2.

The law of algorithm:

Mask calculation: 25,128, 26,192, 27,224, 28,240,298, 30,252,31,254.

Division method:

V average score: divide an address equally into several copies, which have the same number of available hosts.

For example, if the network segment of 192.168.1.0 is divided into 24 segments, if it is divided into two parts, you will get two segments: 192.168.1.0 and 192.168.1.128. The available addresses are 1: 126, 129: 254.

V non-average score: unevenly divided on the basis of average score, the number of available hosts is different. Partition criteria: must be divided according to the number of available hosts from large to small.

For example, there are 126 hosts in department A, 62 hosts in department B, 30 hosts in department C and 30 hosts in department D. for example, there are 126 hosts in department A, 62 hosts in department B, 30 hosts in department D, for example. After uneven division, the address segment is obtained:

Department A: 192.168.1.0 Universe 25 network segment, available address is 1x126.

Department B: 192.168.1.128ax 26 network segment, the available address is 129pm 190.

Department C: 192.168.1.192x27 network segment, available address is 1931-222.

Department D: 192.168.1.224ax 27 network segment, available address is 2250254.

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