Ask HN: What tool to choose for network structure and setup documentation

I have a task to document whole network setup and configuration information. Something similar to disaster plan for other people who woukd work on the network. The company is not related to it industry so it should be easy to understand. It should protect the data that could only be visible for other people who have the password or some other authentication. I'm thinking about mediawiki or tiddlywiki but maybe there is other good suggestions?