Unlike traditional telephone networks, VoIP technology really does not transmit real - time voice . What happens when we make an IP voice call is a transmission of packet data between two IP addresses through a communication channel. Sound waves that we transmit through the terminal are not transmitted directly over the network, but need a VoIP protocol that converts them into data packets that can be transported over the network.
It is important to understand that we are not referring to the program for videoconferencing, such as Skype , but the protocol used. What types of protocols IP voice there? Which are the best known? What are the differences between them? Let's try to explain it to you in this post.
Signaling protocols for IP voice: what they consist of
Protocols differ in their characteristics by the quality of their transmission mechanisms, their architecture, their availability and their degree of security. We are not going to tell you about all that each provider uses, not all versions and standards, but some of the most basic that you should know.
SIP: means "Iniciation Protocol Session" (session initiation protocol) , and to establish multimedia sessions between client and server user for voice or video (teleconferencing). You exchange requests or responses between user agents through a proxy server or redirector. The syntax it uses is similar to HTTP and SMTP, which is what is used in websites and email services.
IAX2: stands for "Inter-Asterisk Echange Protocol" and is an open source . That is, we can change and modify it at our convenience. It is more effective than SIP because the metadata is transmitted in-band , that is, that can be heard by different channels at once.
H.323 is one of the protocols ITU-T (International Telecommunication Union). Originally it was made to transport multimedia applications in LAN networks, but also has been used for IP voice. It is the one used by Microsoft Netmeeting, a Skype-like video call program that was used in XP and Windows 98. It has very little reliability as a signaling protocol in videoconferencing and IP voice transmission.
MGCP: means "Media Gateway Control Protocol". It is characterized by using an MGC as an intermediary between client and server. Its topology includes three components, which implies that the voice passes through a controller before the signaling is transmitted. It has now been replaced by the H.248 standard.
weSIP: it is used by VozTelecom and is simple, flexible and easily scalable. It is a free license server application. It follows the SIP servlet standard, which will allow you to create SIP-based applications very simply.
What other signaling protocols do you know? Do you know what your VoIP provider offers? Leave your comment below, and if you liked this article, share it in the social networks.
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