What is the subnet mask?
subnet mask is a pattern of bits that can be used to insulate specific parts of the Internet protocol address (IP). When it is applied to the IP address, the host address of the network interface and the network routing prefix is created. The directing prefix is also known as a sub -or sub -network. Sub -network masks use network software and hardware to insulate and manage the network parts.
When the subnet mask is logically and added or added using the IP address of the network interface, the initial subnet address of the subnet to which the interface belongs to. The remaining part of the IP network is an interface host identifier. The IP subnet mask of IP version 4 (IPv4) is usually expressed by four octets in a dotted decimal notation. An example is the 32 -bit IP address 192.164.178.5 with a mask of 255,255.255.0. In this case, the initial address or prefix of the subnet direction 192.164.178.0 and the host interface identifier is 5.(CIDR). This means following the prefix with a slash and the number of significant bits in the prefix. For example, the subnet mask 255,255,255,0 has 24 significant bits - in this case all. If this subnet mask is applied to IPv4 192.164.178.5, the resulting prefix in the notation of CIDR is 192.164.178.0/24. CIDR notation is also used with IP version 6 (IPv6) addresses.
In IPv4 networks, all addresses with the same direction of routing on the same subnet. They are usually on the same connection or physical network behind one router. However, the undercoat can consist of several network segments, bridges and switches. The IP packets designed for another direction of routing are handed over by a router connected to the current routing prefix. In IPv6 networks, addresses with the same routing prefixes are not necessarily on the same link.
The concept of the subnet mask was introduced at the beginning of 90 years together with CIDR. Before they determined four bits of IP addresses highthe order to which the address of the address belonged to. The class determined the number of bits in the host direction and identifier, as well as undernet of the starting and end addresses. No subnet mask was needed because the IP address indicated all the necessary information in itself. This type of architecture is known as a class network.
The process of using the subnet mask to divide the network is called subnet. With limited address space available in IPv4 networks, sub -nets can be used for efficient organization of larger networks. IPv6 networks provide extensive address space compared to. IPv6 subnet is more often used to separate local networks from the Internet or to organize networks worldwide.