SIP (Session Initiation Protocol) I trust you’ve heard of VoIP (Voice over IP) by now, which is transmitting voice digitally over the Internet, whether from a VoIP phone, computer, tablet, smart phone, etc. But SIP (Session Initiation Protocol) may have escaped your consciousness. And if it hasn’t, it may have led to confusion due to the fact that many people erroneously use VoIP and SIP interchangeably. Well, they’re not the same. The difference between VoIP and SIP lies, in part, due to one letter—V, as in voice. While VoIP is used for carrying voice traffic, SIP carries all forms of multimedia, including video, and data. But SIP, unlike VoiP, isn’t a service. It’s a protocol.
Protocols are sets of rules enabling messages to be exchanged between devices, whether smartphones, computers, tablets, etc. And when these protocols become industry standards and are adopted worldwide, it enables endpoints to communicate with each other. SIP handles messaging, video, and calls, and HTTP, which you’ve probably seen a gazillion times, takes care of web pages. Now, what protocol do you think is used for VoIP? Yep, it’s SIP. SIP enables VoIP to work.