SIP Routing

Session Initiation Protocol (SIP) is a communication protocol used in VolP networks. SIP routing, also known as SIP trunking, allows users to make phone calls that bypass traditional telephone system.

SIP Routing

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 uni-cast or multicast sessions that do not necessarily involve the initiator.

SIP itself does not provide communication services. Instead, the protocol’s specification defines inter-operable 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.

How SIP routing works

Massive amounts of data are sent across worldwide networks in real-time; SIP routing leverages these transmissions to allow user to establish direct connections for Voice-over Internet Protocol (VoIP). Installed either as a hardware or software, VoIP allows voice and multimedia communication to be transferred across the internet via cloud-based telephony.

One SIP device locates and sends out an invite to another within the network. The device acting as the recipient then replies with a 200 response code — the equivalent of an “OK” — to establish that the invite has been accepted. A similar action then takes place at the other end of the shared conversation, which allows people from all over to connect and transfer information via desktop, desk phones, and mobile devices.

SIP routing for marketing

As a cost-efficient and flexible form of communication, SIP routing has been widely adopted by many companies and most carriers. In the case of marketing, SIP routing has become vital for businesses, especially those with multiple locations. Acquiring multiple phone numbers to assign to their designated locations and using SIP signaling allows calls to be routed to the proper departments and locations.

Options like softphones are especially useful in marketing because of their flexibility and hassle-free installation. More importantly, SIP routing allows business to track which phone numbers and locations are receiving the most calls. This additional insight can give marketers a view of where and when phone calls are received, which helps them measure the impact and ROI of their marketing efforts.


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