A network can work fine without subnetting then why we need to do subnetting? What are the benefits of subnetting?

Subnetting can help you to implement security and network optimization (if you have a very large network to take care of) and more granular, modular control and efficient utilization of Bandwidth and IP Scheme over your network. Hence Improving Network Performance under heavy load and avoiding collisions and retransmission.

1- Ability to organize your resources within a network. e.g.192.168.130.x your network backbone 192.168.131.x marketing department 192.168.132.x sales 2- Ability to secure your resources by placing them into separate subnetworks machines in different subnets need a router to communicate pc_marketing - router- pc_sales routers can (based on security policies) deny or allow connections. e.g. sales can not acces the fileserver of the marketing department, but can exchange documents with other marketing workers. these networks work, like they were phisicaly seperated. 3. speedup your network the "broadcast domain" will be much smaller, than before its like trying to finde someone in a crowded room, yust by yelling his name. the smaller the room, the quicker the answer. network before:192.168.x.x ->255*255 broadcast recipients. after:192.168.131.x max.255 recipients. mainentance will be easier too.

To make separate broadcast domains.

Subnetting will help administrator to divide their LAN and WAN networks so he can limit access to subnets he want.

To help organize the network and ease routing. Create multiple network in a single LAN.

We use subnetting to get following benefits-

• Reduced network traffic
• Optimized network performance
• Simplified management

subnetting helps to understand the host address and network address to find out.in a host address how many host can be assign under a IP addres it can estimate.for example if a Ip address is192.168.1.10/24 that means It class of C.here24 is the host bit and network bit is8.such like subnet helps to us to findo out the information of IP and its details.

Actually thats a great question subnetting has2 reason for doing it, the first one is the management reason were u subnet your network into different subnets to prevent some end devices to access some resources at your network where these resources having different subnet like the VLAN protocol ironically subnetting is more secure then VLANs.. The second reason is what  it is so-called reserving Public IPv4 addresses. 

Hope that u get it.. Enjoy :)

subnetting is very use full for big network environment where lots of department and all..

By doing subnetting you can manage your network well, you get Flexible and Scalability.

easy to identify, easy to give access rights by ip range, manage the trafic... etc

 subnetting is a good way to best manage and administre the network , also it increase the security and a good way to share the ressources..I think there are three kind of subneeting the network , the first one is subneeting geographicly , the second is subneeting by function and the last one is subnetting by the owner ressources..

Basically, subnetting is used to save public IP's. LAN part, usually people dont care if they are in a small or medium network. 

The main concept for subnetting is to save the public IP's. Taking about ISP side, customer request their ISP to provide them public IP with in specific subnet. e.g /29 /30 etc. offcourse you need to pay for public IP.s 

Why IPv6 is in the market? mainreason, we are short of IPv4 public ips's. As you know local ip will never be adversited on internet therefore you need public ips's to take you to internet.