I recently tried to google for "VoIP basics" and a few similar terms. The results were, uhm, unsatisfactory. The pages in the result set all seem to waste too much of the "real estate" with advertisement, the actual content is short and only touches the surface of individual topics.
So perhaps it might help if I write my own Voice over IP Overview. So far, I've covered the digitization of voice, audio codecs, latency and bandwidth optimization, and the Real time protocol. In the next piece, I would like to touch jitter, and then go straight to describing the main VoIP protocols, SIP, and H.323. After that, I would like to discuss for example the topic of VoIP vs. firewalls, and the additional protocols like H.248, IAX2, and SCCP.
What do you think? Will this be useful?