Simple learning IP address protocol

The most important thing to learn about network is the IP address protocol. How do I plan and define IP addresses in the current IPv4 version? Let's take a simple look. First, let's understand the concept of IP address protocol.

IP address protocol

All computers on the Internet must have a unique ID on the Internet as its identifier on the Internet, which is called an IP address. Each data package contains the sender's IP address and the receiver's IP address. The IP address is a 32-bit binary number, which is 4 bytes. For convenience, it is usually expressed as w. x. y. z. W, x, y, and z are decimal integers ranging from 0 to 255, corresponding to a byte in binary notation. This representation is called the dot-decimal representation.

The IP address acquisition method is simply to say that a large organization first applies for several IP addresses from the Internet NICNetwork Information Center, and then assigns them to lower-level organizations, lower-level organizations allocate IP addresses to lower-level organizations. The network administrator of each subnet assigns the obtained IP address to each computer in the subnet. There are three types of IP addresses.

IP address Protocol 1. Class A address

The maximum IP address of A is 0, and the first eight are network addresses. The last 24 are host addresses, which are set by the management organization when applying for an IP address, the network administrator can assign a subnet to each host of the local organization. The value of the first decimal integer of the Class A address ranges from 1 to 126. A Class A address can accommodate A maximum of 224 hosts and A maximum of 16 million Class A addresses. Of course, this is purely mathematical. In fact, it cannot be achieved, because some addresses in a network have other special purposes and cannot be allocated to specific hosts and networks. The numbers in class B and class C addresses are the same.

IP address Protocol 2. Class B address

The first 16 bits of type B IP addresses are network addresses, the last 16 bits are host addresses, and the first and second bits are 1 and the second are 0. The value of the first decimal integer of the Class B address ranges from 128 to 191. A Class-B network can accommodate a maximum of 216 hosts, that is, 65536 hosts, and a maximum of 214 Class-B addresses.

IP address protocol 3. Class C address

The first 24 digits of a Class c ip address are the host address, the last 8 digits are the host address, and the first, second, and third digits are 1 and 0. The first integer of a Class C address ranges from 192 to 223. A Class C network can accommodate a maximum of 28 hosts, namely 256 hosts, with a total of 221 Class C addresses.

There are several special IP addresses. The first one is the return address, which is used for network testing or communication between local processes. The decimal format is 127.0.0.1. The second is the broadcast address, which is used to call computers in the entire network. The last address in the subnet is used as the broadcast address. For example, 16.20.255.255 is used to call all computers in the-type network 16.0.0.0. The third is the subnet address, which is used to identify the subnet. The first address in the subnet is the subnet address, for example, 192.168.0.0.