Subnet Mask in computer network

In this article I describe the Subnet Mask in computer network for CCNA exam. Subnet Mask in computer network related to IP address system in networking. Subnet Mask in computer network denotes the class of IP address used by the device. It is not possible to categorise the IP address without using the Subnet Mask in computer network in computer networking. So we can say Subnet Mask is a part of IP address system in networking.

Before understand the Subnet Mask in computer network you may read about the IP address system here. Communication between different devices on a network depends on the type of IP address. The Subnet Mask define the type and class of IP address for a device. let’s remember the IP address structure in short before understand the Subnet Mask in computer network.

Designing of IP address system

An IP address is combination of 32 bits. Each bit either 0 or 1 but not blank. 32 bits further divided into four Octate. IP can be written in two formats Binary or Decimal. Computer change the decimal into binary during communication. Example of IP in decimal is 10.0.0.0 same in binary 00001010.00000000.00000000.00000000 . User not used the IP in binary system. It is not easy to remember a 32 bit long binary number. During configuration in devices or routing we use the decimal format of IP . Some times IP is also written in Hexadecimal. We discuss about decimal and binary format in this article.

Subnet Mask in computer network

The IP address consist network address and host address. Subnet Mask in computer network denotes the network and host part in a IP address. Subnet Mask in computer network can be used to identify the Class of IP address. We can separate the network and host ID on the basis of given Subnet Mask. In case of classless inter domain routing CIDR we can define the subnet mask according to our requirement. Suppose you have only 25 system in your network then you can use the subnet mask which allow 25 computers to communicate in the network. This practice provide the saving of time and reliability in the network.

The Subnet Mask in computer network is a 32 bit and 4 octate number combination similar to IPv4 address system. Subnet mask also a combination of 1 and 0 like IPv4 address system. The bits which are 1 denotes the network segment and the bits remains 0 denotes the hosts segment. So the whole 32 bit IP address can be divided into network and hosts segment by using the Subnet Mask in computer network.

The large network can be breaks into smaller networks by using the Subnet Mask in computer network. We know the data flow in big network is difficult then in small networks. The point of security is also strong in small network comparison to a large network. We can say the small network are more efficient than the large networks.

Subnet Mask in detail

Subnet Mask in computer network defines the network and host in a network. Subnet Mask distinguish the network ID and Host ID in a packet. A Subnet Mask is logical segment of IP address in a network. Subnet is a 32 bit binary number combination. To make it user friendly and easy to remember the Subnet Mask in computer network allotted in decimal format. Internally the device convert decimal to binary number. 32 bits are combination of 0 and 1.

Subnet make it easy to identify the class of network. Class A, B and C uses default subnet masks “255.0.0.0”, “255.255.0.0” and “255.255.255.0” respectively. The above values are fix for classfull system. When we working in VLSM( Variable Length Subnet mask) and CIDR (Classless Inter Domain Routing) the subnet has not fix value. We can say there is no class in the network.

Structure of Subnet Mask in computer network.

Subnet is a part of IP address scheme for a device in network. It is a logical part of IP address system. Subnet Mask separates the network ID and host ID in the network. In a network the hosts which lies in the same subnet come in particular subnet. Subnetting in a LAN done by defining the subnet in hosts IP address schema. For example all hosts having subnet 255.172.0.0 communicate with each other. Other hosts which do not have subnet 255.172.0.0 can not communicate with them without a router.

Working of Subnet Mask in computer network

The main purpose of Subnet Mask is to create small networks in a large network. The devices belongs to a particular subnet mask can communicate with other devices in the same subnet mask. We can create small networks which can work without interfere each other. Just like VLAN in a layer 3 switch. Router provide the communication between different subnet mask by using the IP routing protocol. The size of different subnet may be different in a large network. The subnet creates according to requirement of networks and hosts. It is possible that a subnet have 20 hosts and other subnet have 200 hosts is a same network. So before creating subnetting we need the size of subnet and number of hosts.

For example the IP address 192.168.10.3 and subnet mask 255.255.255.0 denotes the network id is 192.168.10.0 and the host id is 0.0.0.3. so in this network we can use 256 IP addresses 0 to 255 for hosts. But as we know we have to leave two addresses for network ID and Broadcast ID so we can use 254 device in this subnet of network. The network ID will be 192.168.10.0 and broadcast ID will be 192.168.10.255. This article is just related to the subnet mask so later in next articles I describe the subnetting basics and method of subnetting for different classes.

Important facts of Subnet Mask in computer network

Subnet masking breaks the large network into small sub networks. It is helpful to control the network congestion. You can assume the traffic flow in a large network create data loss and other negative factors. These drawbacks overcome by creating subnetting. Subnetting can be done by defining the subnet in hosts.

Without subnet all device monitor the data flow in the network from all devices. Due to this the data traffic become very congested. Data transfer speed also became slow. You can assume the benefits of subnet . When you design a network firstly you keep in mind how many host can be added in the network. Along with numbers of hosts, number of networks also important.

Uses of Subnet Mask in computer network

The IP addresses can be saved by using the Subnet Mask. Suppose we have a range of IP address for use of 254 devices but we need only 20 devices to work in the subnet. We can save the IP address which can be used by other networks. This practice is not done in local network. When we need to configure large networks like ISP networks then a single IP address have its own value.

To achieve this CIDR and VLSM used in today scenario of networking. The network congestion improved by doing subnetting of the network. Since the number of user and devices reduces in a small network the data flow speed and security improved by using subnetting. Troubleshooting of the network become easy as the size of network reduces by subnetting. It became easy for administrator to manage and maintain the subnetted network.

In this article I describe the Subnet Mask of IP address in computer network for CCNA Exam. I hope you found this article helpful for any query or suggestions you may drop a comment below or contact us. Your suggestions are always welcome by us.