Documenting your network is arguably the least enjoyable part of being an administrator. It is detailed, tedious, and time-consuming work. Yet to neglect it is to put your network, and your job, in peril.

Fortunately, Microsoft Visio can help streamline the process and produce documentation in a visual, easy-to-interpret format. In a recent article, I discussed how you can use Visio to present a high-level overview of your server infrastructure, including the network backplane and simple representations of the servers and other data center equipment. Now, I’ll show you a sample of a major Visio project I once undertook that involved completely documenting a complicated building-to-building fiber optic network I managed.

Let’s biggie size it
For this project, I was working on a 3,000-node network spread across 60 buildings on a college campus. There were 144 pairs of individual fiber-optic strands emanating from a central point on campus to four buildings. Each building was connected to each other with separate fiber runs, which was less expensive than directly connecting all 60 buildings on campus to the central point.

For example, from the central building, we had 36 strands of fiber going in each of four directions. From the next point, there may have been 18 going to the next building, and any pairs that were needed were connected in the middle with a patch cable. This will make more sense when you download and look at the Visio diagram that accompanies this article.

The plot(ter) thickens
When network diagrams begin to get large, you have three choices of how to print out the documentation so that you can view it:

  • Size the diagram to print on a single printed page Visio’s option to automatically fit a document to a specific page size.
  • Print the diagram onto multiple pages and tape them together.
  • Use a plotter and print everything on one huge page.

I prefer the third option, as it’s easier to carry around and hang on a wall. Also, when I have to make changes to the document, I don’t want to have to keep taping up the pieces of paper. And I certainly don’t want to have to squint to read everything on one 8.5 x 11 piece of paper.

It’s always nice to have the option to print to a color plotter, as well. As I tend to be a very visual person, using color can help provide “at-a-glance” details that can be helpful.

As you may have noticed in my server room Visio diagrams, I prefer uncluttered documentation. For some of my granular, detailed documentation, I like to use the actual representations of the network equipment but not for my high-level overviews, such as the server room diagrams or these fiber network diagrams. The purpose of these overviews is to provide easy-to-read and easy-to-understand documentation about the general aspects of the infrastructure. While I might use small icons to differentiate between a hub, router, switch, printer, and server, that is the extent of the detailing that I will do for this type of documentation.

The diagram
For this sample building-to-building fiber diagram, I am presenting a fiber optic network that connects 16 buildings. There will be 64 strands of fiber optic cable emanating from a central point. Each strand of fiber optic cable is numbered. Building 1, where the fiber originates, also houses the network gear. I’ve done my best to show you this sample diagram on a letter-size piece of paper to make it easier for you to print it out and look at it. Figure A shows what you’ll see in the first diagram.

Figure A

This diagram shows the following:

  • A Catalyst 4006 is at the core of this small network.
  • Building 1 has no network gear, but all of the strands of fiber pass through it.
  • Building 2 has two switches, and four strands of fiber are configured to pass through it.
  • Building 3 also has two switches.

The second diagram in the Visio download is too detailed to provide a good screen shot, but you can check it out by clicking on the Diagram 2 tab at the bottom of the Visio page In this one, I have included the IP address of the Layer 3 switch port that each building switch is plugged in to, as well as other network details and diagram information.

Final word
When properly created, the fiber diagram overview offers an excellent representation of your entire network and shows you in a single view your data network traffic flow and free fiber pairs for future expansion. If you use larger paper, you can also put your servers on the page to get an even better view of the traffic flow.

If you have enough time to create more complete documentation, you can change the color of each strand of fiber to match the physical network. At times, this can be useful, especially when you need to have a vendor come in and work on the physical fiber optic cabling plant. Being able to hand the vendor a diagram that’s an exact representation of your network will save time during planning and cut down on possible mistakes.

While I was at this particular job, I was able to make great use of my building-to-building fiber diagram during a network upgrade. For the upgrade, I wanted to be able to place certain pieces of new network hardware in certain buildings. By referring to my diagram during the planning phase of the network upgrade, I could easily create a workable plan and install the equipment without having to wonder if enough fiber was available. I was also able to make the connections at the central point on campus before I installed the equipment in the buildings, since I knew that the fiber strands were available from start to finish.