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Difference between subnetting and supernetting

Subnetting the technique of partitioning a large network into smaller networks. On the other hand, supernetting is the method used to combine the smaller address ranges into a larger space. Supernetting was designed to make the routing process more convenient. Furthermore, it reduces the size of the routing table information so that it can take up less space in the router memory. The well-defined method for FLSM and VLSM subnetting while CIDR supernetting is used.

Subnetting and supernetting are the techniques invented to solve the problem of address exhaustion. Although, the techniques have not been able to eliminate the problem, but they have certainly reduced the rate of exhaustion of the addresses. Supernatism is the reverse process of subnetting.

Comparative graph

Basis for comparison subnettingSupernetting
Basic A process of dividing a network into subnets. A process of combining small networks in a larger network.
Procedure The number of network address bits increased. The number of host address bits increased.
The mask bits are moved to To the right of the default form. To the left of the default form.
Implementation VLSM (masking of variable length subnets). CIDR (class interdomain routing).
Purpose Used to reduce address exhaustion. To simplify and fix the routing process.

Definition of subnetting

Subnetting a technique of partitioning a single physical network into several small logical subnets. These subnets are known as subnets . An IP address consisting of the combination of the network segment and a host segment. A subnet is built by accepting the bits from the host portion of the IP address which are then used to assign a number of small subnets in the original network.

In practice, subnetting converts the host bits into network bits. As mentioned above, the subnetting strategy was initially designed to slow down the exhaustion of IP addresses.

Subnetting allows the administrator to partition a single class A, a class B, a class C network into smaller parts. VLSM (Variable Length Subnet Mask) a technique that divides the IP address space into sub-networks of different sizes and prevents memory waste. Moreover, when the number of hosts the same in the subnets, known as FLSM (Fixed Subnet Mask) .

Definition of Supernetting

Supernetting a reverse subnetting process, in which different networks are united in a single network. During supernetting, the mask bits are moved to the left of the default mask. The supernetting also known as summary is aggregation of router . This results in the creation of multiple host addresses at the expense of network addresses, where basically network bits are converted to host bits.

Supernetting is performed by the ISP rather than normal users, to get the most efficient IP address allocation. CIDR (Classless Inter-Domain Routing) a scheme used to route network traffic over the Internet. The CIDR is a supernetting technique in which the various subnets are combined together for network routing. In simpler words, CIDR allows you to organize IP addresses in subnets regardless of the value of the addresses.

Key differences between subnetting and supernetting

  1. The strategy used to divide a huge network into smaller subnets known as subnetting. In contrast, supernetting the technique of uniting multiple networks into a single one.
  2. The subnetting process involves increasing the bits of the network part from the IP address. Conversely, in supernetting, the host part bits of the address are increased.
  3. To perform subnetting, the mask bits are repositioned to the right of the default mask. As against, in supernetting, the mask bits are moved to the left of the default mask.
  4. VLSM is a method of subnetting while CIDR is a technique of supernetting.

Benefits of subnetting

  • Minimizes network traffic by decreasing the volume of transmissions.
  • Increases addressing flexibility.
  • Increase the number of hosts allowed in the local network.
  • Network security can easily be used between subnets rather than using it across the entire network.
  • The subnets are easy to maintain and manage.

Benefits of Supernetting

  • The size of the router's memory table is minimized by summarizing various routing information items in a single entry.
  • It also increases the search speed of the routing table.
  • Provide the router with isolation of topology changes from other routers.
  • It also reduces network traffic.

Disadvantages of subnetting

  • However, quite expensive.
  • Requires the expert administrator to perform subnetting.

Disadvantages of Supernetting

  • The combination of blocks should be made in power 2; alternatively, if the three blocks are needed, four blocks must be assigned.
  • The entire network should exist in the same class.
  • Once united, it fails to cover several areas.


Subnetting and supernetting both terms have an inverse meaning where subnetting is used to separate the smaller subnets by forming one another by dividing a larger network. Conversely, supernetting is used to combine the smallest address range into a larger one to make the routing process easier and faster. Ultimately, both techniques are used to increase the availability of IP addresses and reduce the depletion of IP addresses.