...type SIP product, but unfortunately not to the general public. These tests, aptly named Session Initiation ProtocolInteroperability tests (SIPITS) are done with the goal of increasing the usage and functionality of SIP and its implementations...
http://www.computerweekly.com/Articles/2007/07/02/225261/SIP-fundamentals.htm
...Accelerate Location-Based Services Ç NEC and SiRF Achieve A-GPS Milestone With Successful Secure User Plane ProtocolInteroperability Testing Ç SiRF Set to Create 'Location Waves' at 3GSM World Congress Ç SiRF GPS Adds Location Awareness...
http://news.thomasnet.com/fullstory/561915
OLYMPIA, WA--(Marketwire - February 9, 2009) - VeriSign (NASDAQ: VRSN) Communications Services, a leader in ENUM registry services, and NetNumber, the developer of the industry leading TITAN addressing and routing servers, announced the successful certification of the VeriSign NRD4.2 software
http://www.marketwire.com/press-release/Verisign-Inc-NASDAQ-VRSN-947105.html