What is a Network Diagram?

Troy Holmes

A computer network is a collection of computers devices connected by communication devices for the purposes of sharing resources. A network diagram is the graphical depiction of the computer network. Typically a network diagram will include a visual schematic identifying computer devices and communication devices within the entire network.

A network hub.
A network hub.

Today there are multiple types of computer networks. These include local area networks (LAN) and wide area networks (WAN). Network diagrams are a used as a tool to describe the physical layout of a computer network. This diagram typically includes the protocols, network addresses, and open ports used by computer devices. The scope of the network diagram can range from a simple single network to complex enterprise network design.

A network diagram of a local area network is a graphical depiction of the computer network.
A network diagram of a local area network is a graphical depiction of the computer network.

A network protocol is the communication standard that defines how information will be transmitted over a network to a computer device. Today there are many protocols available within networks. It is important to define these protocols on the network diagram to ensure proper security and architecture is appropriately applied.

A network port is the end point or channel that is used for transferring data between computer devices. Typically each protocol has a standard default port defined. As an example, most Internet websites use the hypertext transfer protocol (HTTP) protocol. This protocol uses port 80 by default.

Complex computer networks require switches, routers, hubs, and load balancers to ensure efficient communication across the entire network infrastructure. These network devices are typically included within a network diagram. Each communication device has the potential for failure. The network diagram can be used to pinpoint system failures when they occur.

Network monitoring tools are used within most enterprise production networks. These monitoring tools track devices by an Internet protocol (IP) address. When a network device has a failure, error messages are reported to a network administrator. The administrator will use the network diagram to determine the port and IP address of the problem device.

The network administrator has the responsibility of managing and routing network traffic among devices on a computer network. He can be considered the traffic police of the communication highway. The network diagram is an invaluable diagnostic tool for the network administrator in performing his job.

Today there are automation tools that can be used to create network diagrams. These tools range from simple graphical creation programs to complex schematic- generation tools. This software simplifies the management and creation of complex network diagrams. Typically these software packages will include predefined templates based on the network type.

Network diagrams may play important roles in troubleshooting issues with the network.
Network diagrams may play important roles in troubleshooting issues with the network.

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Discussion Comments


@David09 - I’d just like to point that a network diagram is not just limited to computer resources. You can also have a logical network diagram.

For example, my project manager creates a project network diagram that expands upon the basic Gantt chart she uses to track projects. The project network diagram breaks down projects and resources to their granular level, providing a greater level of detail of how much time the project is actually taking and also allowing her to categorize project tasks based on precedence levels (priorities).

It helps us all stay on task and properly focus on the most important needs at any given time, as we juggle multiple tasks.


@hamje32 - I don’t know of any particular free utilities but I am sure they are out there. Just do a search for free network diagram software.

However, if you have Microsoft Office installed on your computer, I think your best choice would be to develop a Visio network diagram. Visio is an absolutely fantastic tool for flowcharting and diagramming.

I use it myself at work, not so much for diagramming but for flowcharting. However, I notice that it does contain a rich set of network diagram symbols for a host of situations, including computer networks with different topologies.

It will provide you with much more capability than you will ever need to draw a physical network diagram for your home setup.


Does anyone know where I can get free network diagram software? I don’t need it for work, but I’m setting up a home network and will add some additional devices.

I could live without a home network diagram, of course, but I’d like to have it as a visual reference as I add the extra peripherals.


I’m not a network administrator, but at our small business the administrator has this very big smart board with a network topology diagram drawn all over it.

It shows the Ethernet connections, all physical devices in the network, including computers, printers, copiers and fax machines.

I think he uses a star topology for his configuration-at least that’s the way it appears from where the lines are drawn.

I believe that with this setup if one piece in the network goes down the whole network can continue to operate. That’s the extent of my limited understanding of network topology.

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