Supernetting in Network Layer

Introduction

Supernetting is one of the main topics in data communication networks or computer networks. The network aggregation goes by many names, such as supernetting, route aggregation, summarization, and so on. Even though there could be a few slight variances technically, we'll make it straightforward and treat all the names of them are same.

The practice of dividing a big network into smaller networks is known as subnetting, and it is well known among those working in the networking industry in subnets area. This is due to the fact that subnetting is a subject that might be challenging to comprehend and that it commonly appears in networking certification tests. Combining/aggregating networks to create a bigger network does the exact opposite.

Definition of Supernetting

"Supernetting" in the network layer can be termed as the process of trying to consolidate a few adjacent subnetted networks into a single, big network known as "supernetting." Super netting is also referred to as route aggregation and route summarization.

The reverse process of subnetting is called super netting. What, however, is subnetting? Subnetting is the method of splitting a huge network into several smaller networks. In contrast, in supernetting, all the smaller networks are connected to one super large network. Supernetting is also called a supernet or a super network.

Where is it Used?

Super netting is most often used in the route summarization process, a summarization in which the routes are combined into several networks with identical network prefixes into a single routing entry that points to a super network that includes all the networks. As a result, both the size of routing databases and the number of routing updates transmitted across routing protocols are greatly reduced.

Super netting is largely employed in the following significant scenarios, such as

  • Route aggregation uses super netting to reduce the size of routing tables and routing table changes.
  • "Super-netting refers to the process of combining many networks into one larger network.

Rules for Supernetting

Some important points need to be followed while implementing super netting. Starting with the connection, the size or network ID must be validated. The few important points are

Super netting involves counting in orders of 2, such as 2 and 4 and 8 and16, etc., just like subnetting does. Make sure your super net just encompasses the networks you intend to aggregate and nothing more when you build one. To prevent routing problems, which we shall describe in a later section, less is preferable.

  • All networks ought to be interconnected. The term for this is contiguous networking.
  • The first Network ID must be perfectly divided by the whole size of the respective Supernet.
  • Every network's block size should not be different and be maintained at the same size. and the block size should be in the form of 2n.

Example for SuperNetting in Network Layer

Now let's look at an example for implementing the process for super netting. As we know, to perform super netting, we need a few individual network ids. and their sub netting mask values and interfaces, respectively.

For example, consider the following network ids:

200. 1. 0. 0
200. 1. 1. 0
200. 1. 2. 0,
200. 1. 3. 0
200. 1. 4. 0

Consider the five networks mentioned above as an example of an interface X. starting the super netting process, the table will look like the below given table.

Network IdSubnet MaskInterface
200. 1. 0. 0255. 255. 255. 0U
200. 1. 1. 0255. 255. 255. 0W
200. 1. 2. 0255. 255. 255. 0X
200. 1. 3. 0255. 255. 255. 0Y
200. 1. 4. 0               255. 255. 255. 0               Z 

The above table is called a "router table."

Our next step is to check the three important rules for the above table.

  1. Contiguous or not?
    You'll see that every network has the same host size when you monitor them all.The maximum host size for the above networks is 256. And all networks are contiguous. The initial network's IP address range is from 200. 1. 0. 255 to 200. 1. 0. 0 respectively. And the following resulting network id is 200. 1. 1. 0 if you add one to the final IP address of the previous network id, which is 200. 1. 0. 255 + 0. 0. 0. 1. By following the above method, you can check to see if the entire network is continuous or not.
  2. Equal Block Size of Networks
    The next rule is to check whether all the networks have an equal size or not. Since all the networks belong to the interface X, they all have an equal size of 256. 256 can also satisfy 2 to the power of 8. That means it is extending the rule. Every network's block size should not be different and be maintained at the same size. as well as the block size being in the form of 2n. 
  3. The first IP address that can be split by the entire size exactly is: When a binary integer is divided by 2n, the last n bits are left over. Therefore, to demonstrate that the size of the Super Net Network is exactly divided by the first IP address. You can determine whether the final n v=bits are zero. The initial IP address in the example is 200. 1. 0. 0, and the total size of the super net is 4*28, or 210. The initial IP address will be subdivided if the last ten bits are zero.

When you draw a bitwise table, the initial IP address's final ten bits are zero. Therefore, the third criterion is likewise met. Organize and reduce network traffic. This will help to address the issue of a lack of IP addresses. the routing table's size. When merged, it can not cover a separate part of the network. All networks should belong to the same class, and continuous IP should be used throughout. This is how you define the supernetting in network layers.

Why is SuperNetting Carried Out?

The basic purpose of supernetting is to improve the routing tables. Routers will share all routes from routing tables in their current state without supernetting. Super netting will condense them before sharing. The number of route updates is drastically reduced via route summarizing. All active networks are listed in a routing table. To find a new path and the best path to a destination, routers share routing tables.

The primary goal of super netting is to make routers' routing tables smaller. For instance, a router can have an aggregated route made up of these 8 independent routes rather than 8 separate routes (all heading to the same next hop). This is significant for several reasons: Because oscillations in one area of the network are not communicated to other areas of the network, they may be isolated, which gives the network stability. It aids in processing and memory power conservation for routing devices. They require less hard drive space and computing power to store and search their routing tables.

The Benefits of Supernetting

Supernetting has many advantages in communication networks. Some of the following benefits of super netting are available. They are

  • The time required to rebuild the routing tables is reduced.
  • It offers a better network overview.
  • The size of the route updates has decreased.
  • It reduces the consumption of resources like memory and the CPU.

What is the purpose of Supernetting?

Supernetting is only possible inside the same address space. It is impossible to combine two or more routes into one if their address spaces are entirely dissimilar. For instance, routes 192.168.1.0/24 and 193.168.1.128/24 cannot be combined. Only a route that has a larger block size than the route being summarized can do so for example, a route with a block size of sixty-four cannot be compressed into one with a block size of thirty-two, but two routes with a block size of thirty-two can be compressed into one with a block size of sixty-four.

Adding the block sizes of all sequential routes and utilizing subnetting, which produces the block size that is equivalent to the result, is the simplest method of determining the summary route. Only the block sizes that are currently available may be summarised. We cannot combine five routes of block size 8 into a single route of block size 40, for example. The valid block size is not 40. Check out the supernetting table above for the appropriate block sizes. The optimum option in this scenario is to maintain the fifth route as-is while summarising the previous four routes into a single route of block size 32.

Conclusion

We conclude with the most important rules for conducting super netting in the network layer. Where this supernetting is performed and why it is carried out is discussed in our article. What is the definition of super Netting, and what are the differences between super and subnetting? Supernetting prevents the efficient use of classful routing protocols like RIPv1. Use classless route advertisements-compatible routing protocols such as EIGRP, OSPF, and BGP to get the most out of super netting.



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