What is SIP and How Does It Work?
All conversations need an introduction and a reliable framework to initiate them. Session Initiation Protocol (SIP) does this job in the digital world. It’s a seamless way to begin and end online conversations.
SIP is a signaling protocol for IP-based telephony applications. It provides the control layer for communications like the establishment and release of a voice call. This communication technology does more than just connect agents to their clients. It allows users to manage and modulate every call that enters their system. What’s more, SIP is content-agnostic. Although SIP was initially designed for voice communication, today it is also used for establishing sessions for instant messaging, video conferencing, SMS, file transfers, and more.
SIP is essentially used for internet telephony and disseminating multimedia between two or more endpoints. For instance, a user can start a telephone call with another user using SIP, or initiate a conference call with multiple participants.
The SIP protocol was designed to be simple, with a limited set of commands. Since it is text-based, anyone can read a SIP message that is passed between two endpoints in a session. The protocol is also flexible and comes with great depth. It was designed to set up real-time multimedia sessions between different participant groups. For instance, apart from facilitating regular telephone calls, SIP can be used to set up video and audio multicast meetings, or instant messaging conferences.
Since SIP is an open standard, it has sparked enormous interest in the telephony market. Marketers of SIP-based phones are witnessing huge growth in this sector.
In this blog, we will get a macro as well micro view of what SIP is, how it works, how it compliments VoIP, and why businesses should invest in this technology:
- What does SIP do?
- SIP Vs VoIP and how SIP adds value to VoIP.
- Features of SIP.
- How SIP enables a VoIP session call flow.
- How SIP works during a voice call.
- Benefits for businesses.
What does SIP do?
SIP is not voice, not video, and not data — the protocol is not restricted to any one media. Also, while it is mostly applied to VoIP, it’s not exclusively a VoIP protocol as well.
SIP launches and ends IP communication sessions that could either be voice calls between two users or a team video conference. It initiates a session by sending messages — in the form of data packets — between two or more identified IP endpoints, also known as SIP addresses. Every SIP address is linked to a physical SIP client — like an IP desk phone — or a software client — like a softphone, for instance.
During these sessions, SIP does not decode or transfer any information. Therefore, the protocol can be used for video conferencing and instant messaging besides making internet voice calls.
SIP’s primary function is to set up calls and end them once they finish. This process involves 5 parts:
- User location: This tells the protocol where the end system that will be used for the call is located.
- User availability: This tells the protocol whether the party that is being called is available to take it.
- User capabilities: This determines the media that will be used for the call.
- Session setup: This involves connecting a call from one user to the other.
- Session management: This involves the running of the call session — for example: transferring and ending a call.
SIP Vs VoIP: How they differ
Since both SIP and VoIP (Voice over Internet Protocol) are both internet-based telephone service technologies, it is common to confuse between the two. The key differentiator between the two is that while VoIP is a type of telephone service, the SIP protocol is used to commence and end communication through VoIP or any other technology.
If your business only requires voice communication, you might want to invest in technologies other than SIP with your VoIP system. However, organizations are rapidly adopting advanced technologies in order to stay competitive and scale rapidly. With its superior unified communications platform and strategies, SIP provides businesses with this opportunity.
Finally, businesses must consider what solutions work best for them. If an organization is considering consolidating its communication technologies, then integration of SIP and VoIP services would be a high-value option for them.
