How To Create Effective Network Diagrams

Easily the most useful – yet often most neglected – form of network documentation is the network diagram. With it, you have access to a visual and textual map of the network that can prove invaluable in all sorts of situations including: troubleshooting, adds/changes, and future roadmap planning. So what does it take to create and maintain useful network diagrams? In this slideshow, I'll provide eight tips to get you started.

The main challenge with network diagrams is that everyone has their own idea of what layout works best. In reality, there’s no real right or wrong. But following some general guidelines will help you create clear, concise and accurate network diagrams that you can use for years to come.

In general, there are a few common pitfalls that IT departments fall into when they create network diagrams. One is a lack of agreement between network engineers/architects as to the overall layout a diagram should take within an organization. From one diagram to the next, each can have its own unique layout, information, and structure. So reading diagrams can be incredibly challenging and time consuming.

Another problem I see on a regular basis is that the creators of the diagrams often fail to understand their target audience. Obviously, the core audience will be architects and support engineers inside the company. But other parts of IT, department managers and external, third-party consultants may also need to read and understand the diagrams. So if the diagrams lack the necessary information or are too complex, they fail to satisfy all of the organization’s needs.

However, the No. 1 culprit of poor network diagram documentation is failure to update diagrams as network adds, changes and modifications occur. So what may have been an excellent document that provided all of the necessary information on day one, ends up simply confusing a year or two down the road.

Continue on to learn how to avoid these missteps and ensure your network diagrams are valuable now and in the future.

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Avoid mixing physical and logical

If you are attempting to show physical connectivity between the access, distribution and core layers in your diagram, don’t also try to cram in any logical information such as VLANs and VRFs. IP address information of the management interface is acceptable, but if both physical and logical information is required, it’s best to create two separate documents.

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Standardize layouts

If you maintain several locations that each require their own network diagram, make sure to standardize your layout and formatting. Doing so ensures that if you can read one, you can read them all. Get a consensus on what works best with the organization and make sure that everyone adheres to the rules.

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Maintain revision information

A critical step in creating network diagrams that's often overlooked is maintaining revision information when the diagram is updated. Make sure to include the name of the person who made the change, the date the document was last updated, and a revision numbering scheme that can show if the update was a cosmetic, minor or major add/change to the previous document. That way, if any questions or issues arise, you have a record of the change.

Scrub sensitive information

Network diagrams often have to be shared with untrusted third parties for a multitude of reasons. However, these diagrams contain highly sensitive information regarding your network that you don’t want to simply hand over. Being able to create a scrubbed set of diagrams that remove this sensitive information yet still convey what the third party needs to know is critical. Most engineers find that using layers in diagramming software such as Viso is an easy way to quickly omit sensitive information in a hurry.

Don’t forget a diagram key

Since there is no true standard when creating a network diagram, the use of lines, circles, and clouds can vary widely from one company diagram to the next. It’s absolutely critical that a diagram key be put in place to explain what the various lines, colors and shapes are meant to represent.

Break out complex diagrams

If you manage a massive enterprise network, it’s easy to fall into the trap of creating a single, giant network diagram to show the entire infrastructure from end to end. But ultimately what ends up happening is that the document becomes overly complex and difficult to navigate. Looking for a specific portion of the network becomes a needle-in-a-haystack exercise. While the idea of maintaining a single diagram may sound appealing, ultimately you’re better off breaking the network up into multiple diagrams that are easier to read and navigate with.

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Use widely available stencils

Instead of using default stencils that come with your diagram software or creating your own, you’re far better off using the  free diagram stencils offered by most networking hardware/software vendors. Not only do they help to speed up the process of diagramming your network with the exact stencils/symbols the vendors use in their documentation, they also can make it easier for vendor support to troubleshoot your network.

Make diagram updates a checkbox

My last tip is probably the most important: Whenever network adds/changes occur, make sure that updating any relevant network diagrams is simply another checkbox within the change control process. Forgetting about updates  can turn previously useful diagrams into an inaccurate and useless mess.

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