Subnets....simplified!

The process of subnetting an IP network can seem confusing to do, but understanding the concept and benefits of having subnets is most important.  The devices within a subnet are addressed with a common and significant bit group in their IP address.  The logical division of the IP address, or two-level classful hierarchy, contains two fields, the network-prefix and host-number.  The creation of a subnet, or three-level subnet hierarchy, is the division of the host-number, the subnet-number and host-number.

So what is subnetting and why is it important?  Subnetting is the logical practice of dividing an IP network into two or more smaller networks.  Devices within a particular subnet can communicated with one another by forwarding packets through local switches.  Traffic between different subnetworks are exchanged through the router, using the default gateway and then the router determines which subnet the packets should be passed to reach the destination host.  This provides security for computers within their subnetwork.  Subnets restrict the broadcast domain to that particular subnetwork.  The benefit of doing this is to save bandwidth for the overall system and information is only disceminated to necessary locations.  In addition, the overall network is less likely to be affected by viruses that could shut down the whole system and is contained only in that particular subnet.  When it comes to managing the overall network, subnets allow easier management and policy creation to be established. 

There are many videos on the internet explaining IP network and subnetting.  The process of subnetting can be explained using different approaches, but the concept and benefits are the same.  You should use the process that works best for you.  When trying to understand subnetting you need a good understanding of the overall network addressing and routing.  Here is the approach I found to be most helpful.