VoIP Protocols
Voice over Internet Protocol (VoIP) is basically a broad term used for a group of communication technologies that is responsible for the delivery of voice communications over IP networks such as the Internet. VoIP is also known as IP telephony, broadband telephony and Internet telephony.
It comprises of various communications services including voice and data transfer via the Internet instead of traditional public switched telephone network (PSTN). VoIP protocols governs the basic steps involved in the process like conversion of the voice analogue signals to voice digital format and translation of the signal into Internet (IP) packets at the point of origination of call so that they can be transmitted over the internet. The entire process is reversed at the receiving end of the call.
Widely used VoIP Protocols are as follows:
SIP (Session Initiation Protocol): It is basically a signalling protocol that is employed widely for operating the multimedia communication sessions involving voice and video calls over internet. SIP also supports many applications like video conferencing, instant messaging, online games and others. The creation, modification and termination of Unicast and Multicast sessions are controlled by SIP protocol. It is used in the varying functions like address or port change, addition or deletion of media streams and inviting more participants.
IAX (Inter-Asterisk eXchange protocol) is basically an open-source protocol that was developed for Asterisk for making effective connections between Asterisk servers. It also establishes the connections from Asterisk servers to home or offices of people using the IAX protocol. The latest version of IAX is IAX2.
The IAX 2 signalling protocol performs basically the similar functions as SIP; however it is not an industry standard. It is more robust and popular due to its open source coding. It is also very easy to implement in situations where NAT (Network Address Translation) is needed.
MGCP (Media Gateway Control Protocol) is a protocol that is implemented for operating VoIP Gateways from external call control elements. It has become widely popular among voice as well as data industries as a robust protocol. It is the latest protocol that scores over the Simple Gateway Control Protocol (SGCP). It is implied for governing media gateways from call agents. In a VoIP system, MGCP can be used along with other VoIP protocols like SIP or H.323. In this arrangement, SIP or H.323 will deliver the call control functionality and MGCP is utilised for managing media establishment in media gateways.
H.323 is a protocol that is standard for multimedia communications. It was created for supporting real-time transfer of audio as well as video data over IP and other packet networks. The standard comprises of various protocols that covers particular aspects of Internet telephony. The H.323 and other related standards are maintained by International Telecommunication Union (ITU-T).
H.323 is being used by several VoIP applications and it supports various call functions including call setup, Call forwarding, Call transfer and call teardown. A H.323 based system comprises of various architectural elements like Terminals, Gateways, Multipoint Control Units (MCUs), etc.
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Category: Types of VoIP Service
