How to draw a network diagram..

[mrunkel]

Folks,

Having been the network business a long time, I'd like to pass on a few pointers that I've learned over the years.

• When drawing a network diagram, think about whether it makes sense to draw a logical or a physical diagram. I'd say 90% of the time, a logical diagram is more useful than a physical diagram.

• What's the difference? A physical diagram shows you the actual devices involved and the cables that connect them to each other. It should have information about which ports are used what color the cables are, etc.

• A logical diagram will show the types of devices and the subnets in the network. It will not necessarily match up with the physical devices in the network. It should be labeled with the IPs of the subnet and the IP of each device. If virtual technologies are used, it probably makes sense to note that they are virtual networks or devices, but they should be drawn the same as physical devices.

• Once you decide which type of diagram you are making, stick with it. Don't try to mix and match drawing types. You need to really fight the temptation to put in too much information especially information from the other network drawing type. For example, switches never belong in a logical network drawing. In place of the switch, draw one or more subnets. Conversely, IP numbering doesn't belong in a physical network drawing. Label the connections with the port name. (e.g. eth0, fa3/1, etc.)

I've attached an example of a logical network drawing a I did for an 911 center in large city. It does actually violate some of my rules, but that's because that's the way the client wanted it.

Comments? What tips do you use to keep your network drawings usable?

Here's a bigger version of the diagram.

[bratsadtar]

Excellent points. Very well explained. Kudos. Shame your image is too tiny to see for those who may not know.
Agree, Good Job.

[mrunkel]

Originally Posted by bratsadtar

too tiny

Oops, fixed it.. Thanks for pointing it out.

[tbelote]

Great post, but I pray no one calls support with a network that complicated

[johnboy68]

Did you use Visio to draw your diagram?

I found an open source program that works well. It's called Dia, you may have heard of it. The project is a little outdated but for those of use who can't afford Visio and don't want to obtain it "other" ways, it works well.

Here is a link to their site - http://live.gnome.org/Dia

[hescominsoon]

There's another actively updated project called network notepad that works very well..

[mrunkel]

Originally Posted by hescominsoon

There's another actively updated project called network notepad that works very well..

While i would love to find another network drawing program besides Visio because of it's tendency to suck monkey b*lls, the website for networknotepd looks absolutely horrible. :-)

The fact that it's Windows only is a downer for me too.

Yes, that was drawn in Visio. I much prefer NetViz, but that got bought by CA and either killed or it got lost somewhere in their huge product line.

Under Linux, DIA is useable, but hardly pretty. On OS X, I've been playing with OmniGraffle, but it is sorely lacking in network icons.

NetViz was great, it actually knew it was a network diagramming tool and understood what data a T1 line should have and what data an ethernet link should have.... Sigh.. Those were the days. It's nicest feature was the exploding diagram where you could have one diagram that was your entire network allowing you to drill down to view additional detail as necessary.

[hescominsoon]

Originally Posted by mrunkel

While i would love to find another network drawing program besides Visio because of it's tendency to suck monkey b*lls, the website for networknotepd looks absolutely horrible. :-)

The fact that it's Windows only is a downer for me too.

Yes, that was drawn in Visio. I much prefer NetViz, but that got bought by CA and either killed or it got lost somewhere in their huge product line.

Under Linux, DIA is useable, but hardly pretty. On OS X, I've been playing with OmniGraffle, but it is sorely lacking in network icons.

NetViz was great, it actually knew it was a network diagramming tool and understood what data a T1 line should have and what data an ethernet link should have.... Sigh.. Those were the days. It's nicest feature was the exploding diagram where you could have one diagram that was your entire network allowing you to drill down to view additional detail as necessary.

my website isn't any nice either..i don't concentrate on my webiste but my clients. For network notepad he most likely is more interested in the product than the website. Windows only..yeah it's a downer..if you don't run windows at all..if you have a windows box it a whirl..

[mrunkel]

Originally Posted by hescominsoon

my website isn't any nice either..i don't concentrate on my webiste but my clients. For network notepad he most likely is more interested in the product than the website. Windows only..yeah it's a downer..if you don't run windows at all..if you have a windows box it a whirl..

The lack of care in the website doesn't reflect well on the care given to the code base. That's all I'm saying. They aren't related, but it doesn't inspire confidence.

[scobar]

I used gliffy.com to create mine. Below is one I made using it.

http://sc0tty8.com/pics/home_network3.jpg