Question

What are IP address classes?

Please explain each class and their characteristics.

Answer 1

IP addresses are divided into 5 classes based on the order of bits in the first octet.

Class A,B,C,D,E

Class A:

For Class A IP addresses,first bit of first octet is always 0 and 7 bits are reserved for NETWORK ADDRESS and remaining 24 bits are used for hosts.First Address is used to identify network and last address is used as broacast address.So total 2²⁴ - 2 IP address are available for hosts.Subnet Mask for Class A IP Address is 255.0.0.0.

Class B:

For Class B IP addresses, first two bits are always 10 and 14 bits are reserved for NETWORK ADDRESS and remaining 16 bits are used for hosts.First Address is used to identify network and last address is used as broacast address.So total 2¹⁶- 2 IP address are available for hosts.Subnet Mask for Class B IP Address is 255.255.0.0.

Class C:

For Class C IP addresses, first three bits are always 110 and 21 bits are reserved for NETWORK ADDRESS and remaining 8 bits are used for hosts.First Address is used to identify network and last address is used as broacast address.So total 2⁸- 2 IP address are available for hosts.Subnet Mask for Class C IP Address is 255.255.255.0.

Class D:

In Class D IP Addresses, first four bits are 1110 and remaining 28 bits can be used for host. IP Addresses of class D are used for MultiCasting. Class D IP Addresses do not have subnet mask

Class E:

In Class E IP Addresses, first four bits are 1111 and remaining 28 bits can be used for host. IP Addresses of class E are used for reasearch. Class E IP Addresses do not have subnet mask.