The importance of Session Initiation Protocol

Session Initiation Protocol (SIP) is used for initiating, modifying, maintaining and terminating real-time sessions that involve voice, video, messaging and other communications applications. The main function of the SIP is to establish a session and afterwards end it when necessary.

SIP is a signalling protocol and not an integrated communication system. This protocol does not encode or transport any audio information in a phone call. Rather it is a component which when used with other Internet Protocols help to construct a complete multimedia architecture.

The network elements in SIP are as follows:

User-Agent: User Agent is the most important one of the Network Elements. It is the endpoint which initiates, modifies or terminates a session through devices like softphone, a mobile, or a laptop. 2 types of User-agents are User Agent Client (UAC) and User Agent Server (UAS)

Proxy Server: The proxy server takes request from a user agent and forwards it to another user. There can be a maximum of 70 proxy servers between a source and a destination. The 2 types of proxy server in use are Stateless Proxy Server and Stateful Proxy Server. To know about VoIP Server check here: Things Must Know about VoIP Server

Registrar Server: Registrar Server accepts registration requests from user agents. This authenticates users within the network. The registrar server stores the URI and user locations in a database. In this turn, helps other SIP servers in the same domain.

Redirect Server: This user agent server generates 3xx redirection responses. It does not initiate any action, instead, it receives requests and responds to the user accordingly.

Gateway: Gateway helps to interconnect a SIP network to other networks. SIP gateways are essential in VoIP networks because they allow multiple audio and video connections to take place over the Internet simultaneously. To know about VoIP Gateway check here: VoIP Gateway important facts that you need to know

Difference between a Session Initiation Protocol and VoIP

• VoIP Technology focuses more on phone calls over the internet. While, SIP is the application layer protocol that establishes, modifies and terminates multimedia sessions like VoIP Calls.
• VoIP is a combination of other technologies and is used within the present day telecommunication network. On the other hand, the signalling protocol, SIP is used within VoIP.
• While VoIP majorly focuses on voice, Session Initiation Protocol deals in all forms of media including voice.

To know more in details about the Session Initiation Protocol and its relation to VoIP Technology check here: Details about Session Initiation Protocol and its Relation to VoIP