IPv4 address format

An important prerequisite for network interconnection is to have a valid address structure, and all users should follow this interconnected network address structure. Because the only way all of the interconnection network users to communicate in the prescribed uniform with each other. This address structure can take many different forms, it can be represented in binary, decimal notation, and even expressed in hexadecimal, such as: 204.71.200.68 into octal form can be expressed as 0314.0107.0310.0104, IP address 204.71.200.68 into ten hexadecimal form can be expressed as 0xCC.71.0310.0x44. IPv4 addresses are currently uses 32-bit binary address, that is a power of 2 32 (4,294,967,296, about 43 million) addresses available in the IPv4 address space. IPv4 addresses to achieve standardization in September 1981, four-bit binary bit group indicated by a computer, into a network and host bits,

for people easy to use, represent decimal address, each 8-bit IP address bit group is represented by a decimal number from 0 to 255, with a dot (.) number and segmented, i.e., a so-called dotted decimal format. The minimum IPv4 address is 0.0.0.0, the largest IPv4 address is 255.255.255.255, but the two values are reserved, not allocated to private end system. Because TCP / IP addresses of all zeros agreement (regardless of how many 0) indicates the local network, to identify a subnet to retain itself; 1 32-bit full address for this site is broadcast, this address is called the limited broadcast address (limited broadcast address ). The host network address bits are all 1's, called direct broadcast (directed boradcasting) address, any point can be broadcast directly to any other network in the internetwork online. The so-called broadcasting, refers to simultaneously send packets to all hosts on the Internet. For Direct Broadcasting (directed boradcasting) address, routers and other network devices addressed by allowing and helping its addressing, direct broadcast (directed boradcasting) has the ability to penetrate subnet address. For the limited broadcast address (limited broadcast address) can only be used for broadcasting this site, there is no ability to penetrate subnet.