Network Foundation-IP addressing

First, classful addressing: classful addressing according to the idea of classifying IP addresses with strict boundaries.

For example, in the IP address, the A _ Magi B _ Q C _ P D, and the E class address is classful addressing.

Benefits: classful addressing strictly distinguishes network ID from host ID, making effective use of address space

Disadvantages: strict classification affects the efficiency of address use, for example, it is possible to use a Class C address as long as the link interconnection address of two addresses.

Second, classless addressing: there is no strict distinction between the number of bits of the network number and the host number, the network number of an IP address is interpreted as a prefix of a certain length.

Benefits: efficient use of address space, more in line with the actual use of address space. And it has flexibility, for example, a classful class An address can be divided into several small blocks of addresses to be assigned to the organization, and multiple class C addresses can also be combined into a large block address.

Classless inter-domain routing: a way to save router resources for INTERNET interconnections with such classless addressing aggregated addresses.

Note:

Private address field:

10.0.0.0 to 10.255.255.255

172.16.0.0 to 172.31.255.255

192.168.0.0 to 192.168.255.255