Visio, of course, the flagship.
But DIA is also quite good...
And no editor-draftsman does not replace your own understanding.
For the subsequent distribution/shipment to the import picture...
And the books...
If you your network imagine clearly, and the pattern will make...
And if not, then I don't know what to suggest.
Network of several levels, which are poorly interrelated.
And at the level of TCP/IP to know the physical topology is not required, but desirable...