Subnetting and supernetting are both logical addressing systems which form part of the Internet Protocol (IP) layer, which create divisions of computer networks into distinct groups with common designated address prefixes. Every computer that is connected to a network requires a unique address, with a subnet mask, which is used to identify and provide an information transfer point on a network of many computers.
The way these addresses are delivered can be either static or dynamic, depending on the type of network. A home network usually has a Dynamic Host Control Protocol (DHCP) server incorporated into the internet router, to provide a unique address for the network card, and to carry out the routing of traffic. Alternatively static addressing can be used by manually setting the IP details of the network card via the Windows Network Connection functions. However ,home networks do not usually require separate subnets.
A large corporation on the other hand, with interconnected offices over a wide area network, would not use a single subnet for all its addressing needs due to the inefficiency of routing traffic over such large distances. In a corporate environment dynamically assigned addresses and routers which facilitate the flow of information between areas, offices or departments are required. Therefore a system to allow division of networks into smaller more manageable pieces is needed, and this can be achieved through subnetting and supernetting.
Subnetting allows a network to be broken into smaller portions, each with its own unique address, and subnet mask, which is designed and implemented in order to speed up a network and prevent packet collision. The arrangement of a subnet is usually done in a hierarchical structure, with branches of different subnets being partitioned from a central backbone in a tree like arrangement. This structure relies on having routers and switches placed in critical network segments, for example between subnet ranges, which organize the flow of data around the network based on the address prefixes of the packets being sent.
This is essential for a fast and efficient network, as well as enabling the computers on each network portion to be hidden from each by the differences in the addressing system. This architecture is useful for any organization, as it allows an extra level of security against network intrusion, increased efficiency of routing, and less collision and loss of packets and information. Supernetting is a similar networking arrangement which combines two subnets by using a Classless Inter-Domain Routing (CIDR) prefix.
This enables two distinctly separate subnets to be combined into one, which is important to note, as it provides conservation of extra addresses, as well as routing efficiency. In supernetting the addresses contained in routing tables are significantly less than in orthodox subnetting, using a large range of addresses. This provides less latency for the routers and therefore more efficiency for the network as a whole.
The routing tables are also more manageable, which under a single subnet arrangement would become very large and also very slow to respond to routing queries. The arrangement of multiple routes into a single entry into the routing table can be compared with a highway system, whereby from a large distance the routing table passes information based on a potential destination, the closer to the endpoint the data gets, the more specific the addressing becomes, much like a sign system on the interstate.
Therefore in conclusion the issue of subnets and routing is one which is very important for home use, small businesses and large corporations, which want to improve efficiency and manageability of a network addressing system. From the home to the office, the arrangement of a network addressing system can be beneficial in many ways from speed to security, and using these two logical addressing systems it is possible to create or manipulate existing networks into a more effective means of communication and to aid business operations.