SBC works after that because both are user agents and therefore the point of contact for the proxy. Whatever the opposition, SBCs became a central part of any SIP deployment.
A more detailed version of the paper is off the website.
A brief introduction to SIP
In the mid-1990s, IETF, the web’s standard body, had already developed various protocols for IP-based telephony services, producing real-time transport protocols (RTPs)  that enabled the exchange of audio and video data. The Session Description Protocol (SDP)  enables the discussion and outline of multimedia data in the communication session.
The Session Initiation Protocol (SIP)  is an attempt by the IETF community to provide a signaling protocol that not only enables phone calls but is often used to initiate a communication session.
SIP specifications describe three types of components: user agent (UA), proxy and registrar servers. The United Arab Emirates is usually a user-appointed VoIP application, such as a VoIP phone or software application.
The registrar server maintains a location database that binds users’ VoIP addresses to their current IP address.
Provides routing argument for proxy VoIP services.
We differentiate between requests and responses when it comes to SIP messages. The response can be either final or temporary. Temporary responses indicate that session placement is ongoing, e.g. The destination phone is ringing.
The session initiation session ends with an SK. A dialog ends with a BYE transaction. Callers and callers counted in the decision scene can re-exchange or exchange various in-dialogue requests such as referee.
In this case the node sends a subscribe request to the server responsible for this event. After this event has taken place, the server will send a notification to the SIP node carrying the event information.
What do SBCs do?
Since their introduction about 10 years ago, SBCs have not been able to meet the growing demand.
General behavior of SBC
Thus, it is not easy to explain any specific SBC behavior that may apply to all or any SBC implementation. However, usually one we will still identify specific features that are common to many SBCs.
The user agent server next door acts as its client. That is, once a proxy receives an SIP request it will store state data.
SBCs also often run dialog identification information from call-ids and tags. Since the SBC-sent invite sets up a replacement dialog, the SBC Message Sequence Number (CSC) also manages the max-forward value. Also you will know more iformation about Brivis Networker Wall Control click here