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In computer networks based on the internet Protocol Suite, a subnetwork, or subnet, is a portion of the network's computers and network devices that have a common, designated IP address routing prefix (cf. Classless Inter-Domain Routing, CIDR). A routing prefix is the sequence of leading bits of an IP address that precede the portion of the address used as host identifier (or rest field in early Internet terminology). In IPv4 installations, the routing prefix is often expressed as a "subnet mask", which is a bit mask covering the number of bits used in the prefix. It is frequently expressed in quad-dotted decimal representation, e.g., 255.255.255.0 is the subnet mask for the 192.168.1.0 network with a 24-bit routing prefix (192.168.1.0/24). Subnet masks in IPv4 do not have to have consecutive bits set, e.g., a subnet mask of "11111111001100110000000000000000" (binary) is permissible, albeit of little additional value, as it does not provide for more efficient address space utilization and cannot be represented in CIDR notation. IPv6 does not use subnet masks and such non-standard routing prefixes are not possible. The routing prefix of a subnet is often further divided into the network's network identifier and a subnet identifier. The network identifier is the leading set of address bits that is common to the prefixes of all subnets in the network. This would typically be the CIDR routing prefix of an organization's entire address space allocation. The subnet identifier consists of the remaining bits in a subnet's prefix after the network identifier. In the cited example, 192.168.0.0 is the network identifier (and 255.255.0.0 the network mask) and "1" is the subnet identifier. In a large organization's network, without subnetting, traffic levels can grow enough that excessive rates of Ethernet packet collisions become a bottle neck due to the nature of Ethernet (cf. carrier sense multiple access with collision detection). For this reason, subnetting can be used to break the network into smaller more efficient subnets. Such subnets can be arranged hierarchically, with the organization's network address space (see also Autonomous System) partitioned into a tree-like structure. Routers are used to manage traffic and constitute borders between subnets. Communication is of specific link-local character (Ethernet broadcast) only within the smallest subnet. A typical subnet is a physical network served by one router, for instance an Ethernet network (consisting of one or several Ethernet segments or local area networks, interconnected by network switches and network bridges) or a Virtual Local Area Network (VLAN). However, subnetting allows the network to be logically divided regardless of the physical layout of a network, since it is possible to divide a physical network into several subnets by configuring different host computers to use different routers. While improving network performance, subnetting increases routing complexity, since each locally connected subnet is typically represented by one row in the routing tables in each connected router. However, with intelligent design of the network, routes to collections of more distant subnets within the branches of a tree-hierarchy can be aggregated by single routes. Subnetting was originally introduced before the introduction of classful network addresses in IPv4 to allow a single larger network to have a number of smaller networks within it, controlled by several routers. Existing subnetting functionality in routers made the introduction of Classless Inter-Domain Routing seamless.

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Q: How do you calculate a subnet mask?
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Related questions

What class has subnet mask 225.225.225.0?

If this is a default subnet mask, then it would be a class C subnet mask. If you are subnetting a network and this is not the default subnet mask, then it could be either a class A or class B.


Defference bw a default subnet mask and a custom subnet mask?

The default subnet mask has a standard size. The custom subnet mask allows you to make subnets that are smaller or larger than the default.


Does ipv6 require a subnet mask?

It does not require a subnet mask.


Subnet mask of 172.16.0.0?

The default subnet mask would be 255.255.0.0


Broadcast ip for 192.168.1.0?

You would also have to know the subnet mask.You would also have to know the subnet mask.You would also have to know the subnet mask.You would also have to know the subnet mask.


What is the difference between a default subnet mask and a custom subnet mask?

A default subnet mask gives you classful addressing on octet boundaries. A non-default subnet mask implies that you are subnetting a larger network into several smaller ones.


What is the default subnet mask for the 198.25.4.129 address?

default subnet mask for 198.25.4.129


Default subnet mask for ip 128.107.23.10?

Default Subnet mask: 255.255.0.0


What is the subnet mask of IP address 188.88.0.0?

The default subnet mask is 255.255.0.0


What is the default subnet mask for the IP address 72.224.56.62?

subnet mask defines how many network bits our network address is using. In default condition subnet mask of the given ip address is 255.0.0.0 subnet mask may change if we do subnetting.


What is Subnet mass?

It is called a subnet mask. A subnet mask is used for dividing IP addresses into host and network addresses.


Give an example of a classful subnet mask give an example of a classless subnet mask?

Classful subnet mask consists of octets of all 1 OR all 0 EX. 11111111.11111111.11111111.11111111 Classless subnet mask consists of octets od 1 AND 0 EX. 11111111.11111111.11110000.00000000


What is a subnet mass number?

The correct term is subnet mask instead of subnet mass. A subnet mask separates an IP address into the host address and the network address. It is a 32-bit number that can mask an IP address.


Is the subnet mask 255.255.0.255 valid for a Class A address?

It's valid and it's called a noncontiguous subnet mask since the 16 bits for the subnet mask are not contiguous. The RFC's, however, recommend against using noncontiguous subnet masks.


How can you change from a subnet mask of 255.255.224.0 to a subnet mask of 255.255.240.0?

2 given subnets


What is the default subnet mask for the IP address 176.43.52.18?

The default subnet mask for176.43.52.18 is 176.43.


What is the subnet mask for 176.42.53.18?

The default subnet mask would be 255.255.0.0 for a class B address.


What may be the subnet mask of 192.168.2.1?

if the ip address is 192.168.2.1 then the subnet mask should be 255.255.255.0


What is the default subnet mask of a class A address?

default subnet mask for class a ip address


What is the subnet mask number to this IP address number 86.158.175.121?

Subnet mask for the above is 255.0.0.0


What is the subnet mask for 192.168.10.62?

The default subnet mask for a class C IP address is 255.255.255.0


What is the motivation behind using a custom subnet mask versus the default subnet mask?

I really wish to know


If internet protocol is 135.210.195.112 what is the subnet mask?

It depends on whether you are using a default subnet mask or you are subnetting the class B network. A default subnet mask would be 255.255.0.0, but if you are subnetting the last 2 octets in the subnet mask could be anything (up to 255 per octet).


When you have a host binary IPV4 address and subnet mask you can calculate its network ID through this logical process?

ANDing


What is the subnet mask when ip address is 216.139.118.8?

There is no set subnet mask for different ip configurations. The most common default subnet mask is 255:255:255:0 though, if that helps.