Studies: Network: Different Address Classes

Summary of IP Address Classes

Class A - 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

• First bit 0; 7 network bits; 24 host bits

• Initial byte: 0 - 127

• 126 Class As exist (0 and 127 are reserved)

• 16,777,214 hosts on each Class A

Class B - 10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh

• First two bits 10; 14 network bits; 16 host bits

• Initial byte: 128 - 191

• 16,384 Class Bs exist

• 65,532 hosts on each Class B

Class C - 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

• First three bits 110; 21 network bits; 8 host bits

• Initial byte: 192 - 223

• 2,097,152 Class Cs exist

• 254 hosts on each Class C

Class D - 1110mmmm mmmmmmmm mmmmmmmm mmmmmmmm

• First four bits 1110; 28 multicast address bits

• Initial byte: 224 - 247

• Class Ds are multicast addresses - see RFC 1112

Class E - 1111rrrr rrrrrrrr rrrrrrrr rrrrrrrr

• First four bits 1111; 28 reserved address bits

• Initial byte: 248 - 255

• Reserved for experimental use

Source