Standards and Tools for Computer Network Diagrams?

_kabel asks: "Recently I've been asked to draw a map of my company's computer network. Gathering the data to do this isn't the problem though - it's drawing it all. This is no easy task, as it contains hundreds of hosts in many locations around the world, linked together with quite a variety of methods (modem, ISDN, ADSL, VPN over Internet and more.) So I have two questions: (1) Are there any standards on computer network diagrams (i.e. the symbols used for the various devices and connections) and (2) are there any tools already available to assist in this?" I know Visio has the capabilities and the symbols to do this, but what about the free-software diagramming tools?

Comments

Standard Symbols 2

[Cmdr. Marille]

Well,
just found this http://www.cisco.com/warp/public/503/2.html>
standard networking symbols from cisco, in a whole slew of formats, with a reference pdf

Why graphical mapping is important...

[Cmdr. Marille]

First of all, yes spreadsheets can be very important for network documentation, but i think a spreadsheet alone is insufficient(at least once the network reaches a certain size)
Think about it, what if something happens to you?
You (and your admin colleagues) may have everything in their minds. Where is which router, what does it connect, what vlans are configured on that switch, what uplinks, stp configuration, redundant interfaces/links.
Now what if sonmething happens to you and your colleagues.
Suddenly someone else has to administer the network, and if the network has a certain size, it will be a taunting task to find out how exactly the topology(physical as well as logical) is structured.

Also a graphical map prevents misunterstandings and generally speeds up the process of making topological changes to your network.
If you have a consultant or external support at your site, it helps. Show them the diagram instead of explaining for half an hour.
For me it also is very nice to have such a diagram, from time to time it's very helpfull to take a step back and look at such a map when troubleshooting.
It helps when you work with other admins, because you can draw and comment on a printed out version of the map.

I think the mistake a lot of people are making(especially with visio VNE) is to win graphic design awards when drawing network maps, that's not the purpose of it.
Keep them simple, with only a limited set of stencils(but then again comment them well).

At last drawing the network maps helps to understand the network, if you for example have a junior admin at your site, let him draw a map, he will understand the network much better(if you build the network yourself, drawing a map obviously very seldom helps your undertsanding ;-) )

Also drawing network maps is important when proposing network designs to customers or suggesting network changes to executives(see, this is very the firewall is going, protecting your precious e-mail server).

Suggestions

[anticypher]

Visio is considered the standard for manually diagramming a network, it's unfortunate the company was borg'd by M$, and the latest version of the product (visio2k) has already shown its direction from professional diagramming tool to org chart tool for micr~1.oft orfice drones. Cmdr. Marille points to a bunch of network icons in his message, every network person should have a copy.

If you can afford it, look into Cisco's Network Designer (assuming a large part of your kit is cisco), which autodiscovers your network, similar to how HP openview works, and it also uses CDP info and examines cisco configuration files to understand complex interconnections. If you can't get a copy from cisco, NetFormX sells it to everyone else. The neat thing about CND is you can click on each generic icon, replace it with a specific model of equipment, and it builds a database of every component on the network. I've seen clients extract that data automatically into an inventory database for the beancounters.

Other posters are listing all the free alternatives, but if you really have a globe spanning network with that many machines and routers, spend a little on either visio or CND. Good documentation is a major part of network administration, don't skimp on the tools. If you have to skimp, I'd go with dia, or maybe Kivio is stable enough now.

When you are trying to build a document base, first find out the largest size printer you will have regular access to. Make all your pages that size, put a nice border just inside the print margins, and have a small info block in one corner just like professionals do. Test how small you can make your fonts so you can read a photocopy of the original. Once you know the limits of your printed pages, then start your documenting project. Break the network into logical maps, representing regional areas, physical locations, protocol types, vpn tunnels, backbones, hosts, etc.

You can't fit an entire network onto a single sheet of A4 (8.5x11) paper, no matter how hard you try. I can barely fit my home network diagram onto an A3 page. Move all the important non-graphical information onto other pages that accompany the pretty picture page. Make a book where each diagram has a few pages of text descriptions, specs, snippets of configs, spreadsheets, caveats and reasons for doing screwy things.

When you have successfully documented your network, any PFY should be able to flip through the pages and be able to fix problems with only a few minutes of study (yeah, right!).

the AC