IP Defined address ：
1,IP An address is used to identify a node in a network （ Or network device interface ）;
2,IP Addresses are also used for IP Addressing of packets in networks ;
3, One IPv4 Address right 32 position , Usually used “ dotted decimal ” express .
Binary , decimal system , The conversion relationship between hexadecimal three
IP Category of address
IPv4 All in all ：2^32=4,294,967,296 individual
（ be careful !!!：127 The address is tested as a local loopback , To test the TCP/IP Is it normal ）
IP The address is determined by the network part , The host part consists of these two parts .
give an example ：
If there is an express , From Huawei base in Shenzhen , Send to a specific place in a district of Shanghai . Express companies in Shenzhen don't care which specific location to send to Shanghai , Just send it to Shanghai . here , This area of Shanghai is equivalent to
Area number （ The network part ） The address of the city is equivalent to that of Shanghai （ That is, the host part ） In network devices , Routing device “ Only care ” network number .
IP Address , How to distinguish between network part and host part
NetMask Netmask （ Equivalent to green leaves ）
The netmask is 32bits, And IP The number of digits in the address is the same
The network mask subbinary representation is represented by the 0,1 Constitutive
The value is 1 Of bit corresponding IP Network bit of address ; The value is 0 Of bit corresponding IP Host bit in address , To help identify a IP Network bit and host bit of address .
IP Communication network type
unicast , radio broadcast , Multicast
IP Address type
Variable length subnet mask （VLSM）
Why divide subnets ?