What is the address mask?

Address Mask is a term used in computer networks that describes part of the Internet protocol address (IP) that will represent the undercoat. The most common name for this is a subnet mask or a bit mask. The address mask is represented in binary format, which means in 1s and 0s.

To actually understand the address mask, we need to understand what is undercoat and how the IP address or network address works. Usually, the IP address will have either 8-, 16- or 24-bit network IDs used to distinguish between different computers in the network. The undercoat allows you to expand these bits, so instead of having only one IP address or network address can be two or three; This is called subnet. The basis is a network undercoat that falls into one of the three types of IP addresses: Class A, which is an 8 -bit network; Class B, which is a 16 -bit network; or class C, which is a 24 -bit network.

For sub -to work, the router must know which part of the host ID - a computer that is on the network - the network ID will be used. This is the placesO, where the address mask comes. Computers talk to each other in a binary place, ie 1s and 0s. In the network, the router is looking for both the IP address and the address mask. He then performs a comprehensive operation in which he discovers the network ID. The network ID may look like 192.168.2.0.

subnet masks are determined by the class of IP addresses, ie class A, class B or class C, for most private networks, including well -known internet service providers, the subnet mask will be something within 255.255.255.0, which will be set to the C -Class network. If the first bit is 0, the mask is part of class A; If the first two bits of are 10, then it is part of class B; and if the first three bits of 110 are then it is a class C.

Address masks are always composed of bits that are set to 1, so only nine values ​​are possible for the address: 0, 128, 192, 224, 248, 252, 254 and 255. The minimum number for Network ID is eight bits, so the first eight BIm masks under the Sugar will always be 255.