What was sip modeled after

Cloud-native visibility, detection, and response for the hybrid enterprise. Find white papers, reports, datasheets, and more by exploring our full resource archive. The Session Initiation Protocol is a signaling protocol that enables the Voice Over Internet Protocol VoIP by defining the messages sent between endpoints and managing the actual elements of a call.

SIP supports voice calls, video conferencing, instant messaging, and media distribution. Check this blog post for in-depth information on SIP architecture, messages, and methods! SIP is just one method of deploying VoIP; its primary benefit is the fact that it provides a direct connection between private or local telephone systems private branch exchanges, or PBX and the public telephone network. This way, individuals and businesses don't need a legacy telephone line in order to connect.

The SIP messages describe the identity of the participants in a call, and how the participants can be reached over an IP network. SDP Session Description Protocol will define the type of media channels that will be established for the session — typically this will declare which codecs are available, and how the media engines can reach each other over an IP network.

Once this exchange of setup messages is completed, the media is exchanged using yet another protocol, typically RTP Real-Time Transmission Protocol. RFC SIP trunking explained. Check your inbox!

Click on the button in the email body to verify your email address - if you can not find it, check your spam folder. The 1 Communications System! Then, it is the responsibility of the proxy server to decide which phones to "ring" when a call comes in for Bob. With SIP, that could mean selecting a single phone to ring, or just ringing all the phones at once. Because SIP is used for call control, features such as voice mail and auto-attendant are not part of the SIP protocol itself.

Instead, they are provided by end points that send and receive calls themsleves. For example, the Asterisk SIP proxy server tested as part of our iLabs demonstration includes both voice mail and auto-attendant.

In other cases, such as a conferencing server with its heavy digital signal processing requirements, you might want a separate dedicated device. SIP's easy-to-read format has made implementation and debugging of SIP easier than other similar protocols, such as H. Here are the latest Insider stories. More Insider Sign Out.

Sign In Register. Sign Out Sign In Register. Latest Insider. Check out the latest Insider stories here. More from the IDG Network. SIP terms. Advanced SIP interoperability is slow in the making. Testing shows VoIP a big winner. Function Description User location and registration End points telephones notify SIP proxies of their location; SIP determines which end points will participate in a call.