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【转】Classful IPv4 addressing definition

Classful addressing definition

 

ClassLeading
bits
Size of network
number
 bit field
Size of rest
bit field
Number
of networks
Addresses
per network
Total addresses
in class

Start

address

End address
Class A     0     8     24     128 (27)     16,777,216 (224)     2,147,483,648 (231) 0.0.0.0 127.255.255.255
Class B     10     16     16     16,384 (214)     65,536 (216)     1,073,741,824 (230) 128.0.0.0 191.255.255.255
Class C     110     24     8     2,097,152 (221)     256 (28)     536,870,912 (229) 192.0.0.0 223.255.255.255
Class D (multicast)     1110     not defined     not defined     not defined     not defined     268,435,456 (228) 224.0.0.0 239.255.255.255
Class E (reserved)     1111     not defined     not defined     not defined     not defined     268,435,456 (228) 240.0.0.0 255.255.255.255

【转】Classful IPv4 addressing definition