SIP is the Session Initiation Protocol. In IP and traditional telephony, network engineers have always made a clear distinction between two different phases of a voice call. The first phase is ...

HTML structure 100% still matters for accessibility. Accessibility is not a direct ranking factor, though, so it’s a bit outside the scope of this article.

Session Initiation Protocol (SIP) is a control (signaling) protocol developed by the Internet Engineering Task Force (IETF) to manage interactive multimedia IP sessions including IP telephony ...