For example
Class B addresses host number 2 to the power 16-bit 16 = 65536
Remove all-zero and all-one remaining outside the host address is available: 65534
1. Class A IP address
A class A IP address of a network address and byte 3 byte consisting host address, the network address of the most significant bit must be "0", the address range 1.0.0.1-126.255.255.254 (binary notation as: 00000001 00000000 00000000 00000001-- 0,111,111,011,111,111 1,111,111,111,111,110). A network has available Class 126, each network can accommodate 1,677,214 host.
2. Class B IP addresses
Class B IP address consists of two bytes of network and host addresses composed of 2 bytes, the maximum bit network address must be "10", the address range 128.1.0.1-191.255.255.254 (binary representation: 1,000,000,000,000,001 0,000,000,000,000,001 --10,111,111 1,111,111,111,111,111 11111110) into. Class B network has the available 16384, 65534 can accommodate each network host.
3. Class C IP addresses
A Class C IP address of 3 bytes of network and host addresses composed of 1 byte, the most significant bit network address must be "110." Range 192.0.1.1-223.255.255.254 (represented as binary: 1,100,000,000,000,000 0,000,000,100,000,001 --11,011,111 1,111,111,111,111,110 11111110) into. Class C network up to 2,097,152, each network can accommodate 254 hosts.
4. Class D addresses are used for multicast (Multicast).
Class D IP addresses of the first byte to "1110" starts, which is a special reserved address. It does not refer to a specific network, currently used in this type of address is multicast (Multicast) in. Multicast group address is used to address one computer, it identifies a set of computer share the same protocol.
Address range 224.0.0.1-239.255.255.254
5. Class E IP addresses
With "1111" began, reserved for future use.
Class E addresses are reserved, only for test and development use.
All zeros ( "0.0.0.0") refers to any network address. All "1" of the IP address ( "255.255.255.255") is the current subnet broadcast address.
Reference from: http: //blog.csdn.net/ylqmf/article/details/4970213
Supplement other knowledge:
LAN protocol structure involves only the physical layer and the data link layer (medium access sublayer LLC sublayer +)
LAN architecture follows the IEEE 802.2 standard is developed, in this architecture, only defines the minimum corresponding to two ISO / OSI seven-layer reference model, namely the physical layer and the data link layer. Wherein the data link layer is divided into two sublayers, a sub-layer is a media access (MAC) is closely related to the physical layer, and the other is to provide a unified service to an upper layer logical link control sublayer (LLC.), The medium access sublayer and the physical layer together constitute the other standards such as IEEE 802.3,802.4,802.5, logical link control sublayer is the standard IEEE 802.2.
TCP / IP port occupies two bytes, 0 to 65535. Port is divided into three categories:
1. The common port (0 to 1023), assigned by IANA mechanism, also known as "well known ports";
2. Port Register (1024 to 49151), by a company or other institutions registered with the Internet Corporation for Assigned Names and Numbers (the ICANN) port number;
3. Dynamic ports (49152 to 65535), the port number used by the client, the use of dynamic allocation.
