This text is an attempt to provide a concise overview of the VoIP technology and the protocols behind it. The most popular sections cover SIP: Introduction to SIP, SIP Messages, SIP Call Flow, and SIP — Session Description Protocol. The other pieces deal with digitization of voice (start with this one if you are new to VoIP), audio codecs, codec latency vs. bandwidth optimization, audio jitter (a bit of math here), the Real Time Protocol, introduction to H.323, description of H.323 call flow, and H.323 call signalling optimizations.
This Python script is a platform-independent site map generator. It crawls a web site starting from a given URL and outputs XML sitemap file that you can use for Google or other search engines. The most recent version 1.1.0 adds support for the robots.txt file and the 'nofollow' tag.
Have a look at the Freemind tutorial if you are new to the Freemind mind-mapping app (applies to Freeplane as well). As an example of how to describe a complex topic with a mind map, I'm adding two larger maps: One that describes a typical CRM system, the other one contains notes about use cases. Both available in the Freemind file format.