It’s easy to get lost in the technological babble of our industry. We are awash in acronyms, product names, standards (real and pseudo), protocols, and vendor specific terminology. I can’t tell you how many times I thought I was hearing something new only to realize it was just another way of expressing an old idea. It’s almost as if some people use their mastery of mnemonics as a game and the one who can befuddle the most, wins.
In my latest article for No Jitter, I tie together a number of topics previously addressed here on SIP Adventures.
Tao, Zen, and Tomorrow 
Excellent!
Andrew,
thanks for sharing such great info . Do you have the information about the rtpmap values 96- 127 and their purpose. I mean when and which number to use ?
Take a look at this: http://www.iana.org/assignments/rtp-parameters/rtp-parameters.xhtml
And this: http://tools.ietf.org/html/rfc3551