SIP has changed since the publication of RFC 3261 in 2002 - ten years ago. One important addition to the SIP family of protocols is ICE. ICE assists in media setup over complicated networks, like NAT and with dual stack IPv4 and IPv6 interfaces.
This presentation is part of Edvina's SIP 2012 project, to help customers write better specifications when purchasing SIP solutions. Read more on http://edvina.net/sip2012