What is a Network Diagram
A network diagram is a picture representing one or more aspects of a computer network. In addition to showing information about network devices, network diagrams should also show the relationships between devices.
Device information such as hostnames, IP addresses, DNS names and interface identifiers are commonly presented in network diagrams. Figure 1 below shows different labels that can be associated to a single network device.
Network diagrams can represent very small networks such as the one listed above, or very large corporate networks consisting of tens of thousands of end nodes. No matter what size the basics are always the same. The diagram should present enough information for an engineer or computer technician to be able to plan troubleshooting or an upgrade just from the information on the diagram.
Related Information
What is a Network Diagram Used For?
There are many purposes for a network diagram, in fact, the purpose of the diagram dictates the kind of detail that is required. Here are some common uses:
Troubleshooting and support - The most common use us to understand what components reside on the network and how they fit together. When one component fails a network diagram can be used to quickly identify dependencies or logical identifiers such as hostnames or IP addresses.
Planning Upgrades - Once again, diagrams can be used to detect dependencies when planning an upgrade. But with upgrades they can also be used to figure out how (and where) to connect the new device and possibly even give an indication of the capacity required by the upgraded device.
Show Different Network Layers - With todays technology networks can host a number of different logical layers which can differ significantly from the physical layout. An example is on a network where VPNs, tunnels or VRFs are used.
Capacity Management - Sometimes diagrams can highlight bottleneck or oversubscriptions. Depending on what information the diagram shows, they can also hold a lot of information about capacity including bandwidth, free space, memory, and compute power.
Disaster Recovery - Network diagrams that detail physical connections as well as logical addresses and services should be part of any Disaster Recovery Toolkit. These diagrams should be presented in a way that would enable an engineer to rebuild it from scratch without prior knowledge of the network.
Sales or Brochures - They say a picture tells a thousand words. Diagrams for services that may otherwise be complex or wordy to explain can be very beneficial.
Presentations - Network diagrams can also help to bridge the communication gap between technical and non-technical staff. They can make an abstract concept appear simple.
With all of these uses it is conceivable that a single network may be drawn a number of different ways to fit the bill. For example,
- Consider a network that is presented by a vendor. A sales diagram may be used that shows the high level network as well as business benefits associated with each component.
- Once the vendor is engaged, the network is presented to key stakeholders and is represented by a new diagram that shows how each business unit benefits or connects to the network.
- Finally the network is built be engineers and physical as well as logical diagrams are created for troubleshooting and support purposes in the future.
Basic Components
The basic components of a network diagram include the network nodes themselves, the links that connect the network nodes, any third party services such as an Internet link and internal services such as Web Servers or Application Servers.
How Much Detail is Required
The amount of detail entered into the diagram depends on what the diagram will be used for. In the example above the home network diagram could be used to troubleshoot the Internet connection.
As the complexity of the network increases in may be more difficult to include all details into the one single diagram. Sometimes two or three diagrams are required of the same network, each representing one aspect such as physical connections, routing or virtualization.
How to Draw a Network Diagram
For a detailed plan on how to draw a network diagram please visit the linked page. It is important, however, to understand what a network is and how it will fit together before drawing the network diagram.
This example network diagram shows the components of a home based computer network. It consists of a modem, a computer and a printer and it shows how they all connect together. It also displays the Internet Service provider details making this diagram very useful for troublshooting or upgrading any aspects of this home network.
