The subnet mask is a 32-bit address, is a technique used in conjunction with the IP address. Its main role has two, one for shielding part of the IP address to distinguish the network ID and host ID, and shows that the IP address is on the LAN, or on a remote network. Second, for a large IP network is divided into small subnetworks.
Use IP subnet is to reduce waste. Because with the development of the Internet, more and more network produces some network as many as several hundred, some only a mere few, so you waste a lot of IP addresses, so subnetting. Use a subnet can improve the efficiency of network applications.
The method belongs to the same network segment is determined by the subnet mask is both a computer, the computer converts the decimal IP address and subnet mask in binary form, then a binary "and" (the AND) is calculated (per 1 was 1, was a failure 0), if the result is the same, then the two computers on the same network segment.
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