The most important reason is SIP is good and cheap. So, if operators want to earn more money from their HW and deployed APs, they must control SIP applications extension. And then we can see now, in China, many local operators do SIP applications but not tell their customers. Most of customers unware what happen. If all they know they can try another cheaper way to communicate, the world changed.
Back to technology!
Mr. Proulx give an easy understanding introduction and sample for us to learn how to develop a SIP application, the flow, environment, and the key points. Thanks.
In here, I just metion these:
SIP offers some definite advantages:
Stability: The protocol has been used for years now and is rock-solid.
Speed: This UDP-based tiny protocol is extremely efficient
Flexibility: This text-based protocol is easily extensible. Security: Features like encryption (SSL, S/MIME) and authentication are available. Extensions to SIP offer other security features.
Standardization: With the entire telecommunications industry moving to it, SIP is rapidly becoming the standard. Other technologies may have some advantages over SIP, but they lack global adoption.
Read more at dev2dev.bea.com/pub/a/2...