Hi. I need to create a diagram for a WAN/LAN for a company with a head office (10000 users) & 4 branches connected via a VPN.
Hosts as follow,
HO: 10000 hosts
Branch 1: 9000 hosts
Branch 2: 4000 hosts
Branch 3: 2000 hosts
Branch 4: 1500 hosts

How do I go about giving the hosts IP Addresses using subnetting?

Edited by brennyt: looks confusing

4 Years
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Last Post by JorgeM

This sounds like a school project. There's quite a bit of info that is needed to be able to provide a simple, one line answer.

In addition, I doubt that anyone on this forum is going to do this project for you.

What have you done so far and what specific question do you have about a particular part of this project?


The project is just to design a WAN/LAN diagram & indicate the LAN for each branch, servers, routers, the VPN it uses, the firewalls & the UPS. Also, I do not want anyone to do it for me. All I want is some guidance with regard to subnetting so many hosts. I've just made a pencil drawing of how the network might look.

Edited by brennyt: more information


Ok, so the diagram is a good start. If you need a refresher on the basics of IP subnetting, take a look at this summary:

CIDR and Subnetting

Because of the number of hosts that your network will contain, you'll probably need to consider starting with a class A address. For example, a 10.x.x.x Since you have routers between your WAN connections, setting up routing is going to be relatively easy with this design. As you start to divide up the IP scheme, you apply the correct subnet mask to accomodate the number of hosts per subnet.

So, in a simple example, say you have two buildings each with 10 floors and 200 hosts per floor. That's a total of 20,000 nodes. While you may have 20-30 subnets, the subnet assignment is organized and not random. So in building a you would assign and building B Now in building A since you need 200 available IPs for each floor, you would assign a /24 mask such as:

Building A ( - Floor 1 - Floor 2 - Floor 3

Building A ( - Floor 1 - Floor 2 - Floor 3

Between the buildings, the routing tables can be kept clean and organized where in summary, packets that fall in the go to building A, and go to building B, and so on for all of other buildings in your design. The routers that connect the WAN do not have to know about every subnet in each building, if the subnets are organized in this manner. The WAN routers just forward the packets to the LAN routers within the buildings.

I also have an online subnet calculator that you can use to help you quickly determine the number of hosts per subnet..

IP Subnet Calculator

This should be enough to get you going.

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