Concept of VoIP protocol

Next we will introduce the VoIP protocol. We all know that VoIP is one of the most popular network businesses. The Application Basis of this Service is also a VoIP protocol. We will introduce this protocol in detail.

VoIP protocol

Currently, VoIP protocols are commonly used, such as H.323, SIP, MEGACO, and MGCP ｡

H.323 is a ITU-T standard originally used for multimedia conferencing on a LAN and later extended to over VoIP ｡

This standard includes both point-to-point communication and multi-point meetings ｡

H.323 defines four logical components: terminal, gateway, gatekeeper, and multi-point control unit (MCU )｡

The terminal, gateway, and MCU are regarded as terminal points. Session Initiation Protocol (SIP) is the IETF standard for establishing VoIP connections ｡

SIP is an application layer control protocol used to create, modify, and terminate sessions with one or more participants ｡

The structure of the SIP is similar to that of HTTP (client-server protocol ｡

In the VoIP protocol, the client sends a request and sends it to the server. After the server processes the request, it sends a response to the client ｡

The request and Response Form A transaction. The Media Gateway Control Protocol (MGCP) is a VoIP protocol proposed by Cisco and Telcordia, which defines the Call Control Unit (call proxy or media gateway) communication Service with the Telephone Gateway ｡

MGCP is a control protocol that allows the central console to monitor IP Phone and gateway events and notify them to send content to the specified address ｡

In the MGCP structure, Intelligent Call Control is placed outside the gateway and is handled by call control units (call agents ｡

At the same time, call control units are synchronized with each other and send consistent commands to the gateway ｡

Media Gateway Control Protocol (Megaco) is the result of the joint efforts of IETF and ITU-T (ITU-TH.248 recommendations ｡

Megaco/H.248 is a Protocol Unit used to control physically separated multimedia gateways. This allows you to separate call control from media transfer ｡

Megaco/H.248 describes the connection between a media gateway (MG) used to convert a circuit to exchange voice to packet-based communication traffic and a media gateway controller used to define the Service Logic of such traffic ｡

Megaco/H.248 notifies the media gateway to connect data streams from outside the packet or unit data network to data packets or unit data streams, such as real-time transmission protocol (RTP )｡

According to the relationship between the VoIP protocol structure and gateway control, Megaco/H.248 is essentially similar to MGCP, but Megaco/H.248 supports a wider range of networks, such as ATM ｡