Word of the Day: Session Initiation Protocol (SIP)

Word of the Day Daily updates on the latest technology terms | July 17, 2018 Session Initiation Protocol (SIP) Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, modifying and terminating real-time sessions that involve video, voice, messaging and other communications applications and services between two or more endpoints on IP networks. SIP was developed by the Internet Engineering Task Force (IETF) to address the evolving needs of IP-based communications. Native support for mobility, interoperability and multimedia were among the drivers behind SIP's development. SIP complements other communications protocols, such as Real-Time Transport Protocol (RTP) and Real-Time Streaming Protocols (RTSP), used in IP-based sessions. SIP features The SIP communications protocol determines five attributes when establishing and terminating multimedia sessions: User location User availability User capabilities Session setup Session management Different types of multimedia SIP sessions include internet telephony calls, video conferencing and other forms of unified communications. The protocol can be used to invite participants to unicast or multicast sessions that do not necessarily involve the initiator. SIP itself does not provide communication services. Instead, the protocol's specification defines interoperable implementations of SIP features, called primitives, that can be used to facilitate different services. Primitives allow additional information to be embedded in a SIP message, such as linking a user's photo to directory information to enable media-rich caller ID. SIP also supports name mapping and redirection services, which are two key ways the protocol enables mobility. Users and endpoints are detected with a single identifier, known as a uniform resource identifier (URI), which is independent of their network location. URIs are alphanumeric, using a syntax that looks more like an email address than a phone number or IP address. In addition to real-time services, SIP can be used for asynchronous event notifications, such as automatic callbacks, message-waiting indicators and buddy lists based on presence. How does SIP work? Like HTTP or SMTP, SIP works in the application layer of the Open Systems Interconnection (OSI) communications model. SIP is a request-response protocol, receiving requests from clients and responses from servers. Requests can be sent through any transport protocol, such as UDP, SCTP or TCP.e SIP determines the end system to be used for the session, the communication media and media parameters, and whether the called party agrees to engage in communication. Once these are assured, SIP establishes call parameters at either end of the communication, also handling call transfer and termination. The protocol is supported by both IPv4 and IPv6. Quote of the Day "Deciding between a centralized or distributed SIP service deployment depends largely on an organization's UC architecture and infrastructure, as well as the layout of the business as a whole." - Michael Brandenburg Trending Terms IETF RTP telephony unified communications primitive SIP trunking Learning Center H.323 vs. SIP: What's the difference? Look at the differences of H.323 vs. SIP in this comparison of two primary VoIP and multimedia IP standards. Update session border controllers routinely for secure SIP trunking Session border controllers play an important role to secure SIP trunking deployments, but they need constant updates to remain effective. Avoid these four SIP deployment pitfalls Learn the four pitfalls organizations must avoid for a successful SIP deployment, from hidden fees to improper firewall configuration. Is the virtual SBC market poised for rapid growth? Session border controllers offered as a service could cut costs for enterprises and provide additional deployment options. But is a virtual SBC right for you? How do you choose your SIP service deployment model? Choosing the right SIP service deployment model can be tough. Expert Michael Brandenburg explains how to choose between centralized and decentralized SIP. Quiz Yourself There are a number of methods you can use to capture VoIP calls ___ a LAN. a. off b. off of Answer Stay in Touch For feedback about any of our definitions or to suggest a new definition, please contact me at: mrouse@techtarget.com Visit the Word of the Day Archives and catch up on what you've missed! FOLLOW US About This E-Newsletter This e-newsletter is published by the TechTarget network. To unsubscribe from Whatis.com, click here. Please note, this will not affect any other subscriptions you have signed up for. TechTarget, Whatis, 275 Grove Street, Newton, MA 02466. Contact: webmaster@techtarget.com Copyright 2018 TechTarget. All rights reserved.