The Backbone of Voip

Protocols

"Protocols”, are the standards or rules that activate the connection, data transfer and communication between the two computer systems. The Protocols define the technique of data compression, error checking which is applicable on data transfer. Protocols come in many kinds and a form, “Internet Protocol”, is one of the widely used open-system protocol package. This package includes the lower layer protocols like the “Transmission control protocol”, the “internet protocol”, applications such as file transfer, terminal emulation etc. VoIP makes use of the “Internet Protocol” for transmission of voice data between two computer end-points. Below we describe some of the commonly used protocols in Voip Solution.

VoIP Protocols

“Voice over Internet Protocol [VoIP]”, as the name says, makes use of the protocols to transmit voice and other data. The two most common standard protocols used by the VoIP companies are, “the Session Initiation Protocol (SIP)” and “H.323 Protocol”. VoIP phones send SIP and H.323 messages to source and destination PC’s to register each other and initiate the call. The “SIP”, “H.323” protocols are empowered with various features, few of them are highlighted in the below discussion.

The Session Initiate Protocol [SIP]

“Session Initiate Protocol”, an Internet Engineering Task Force’s standard that manages multimedia conferencing on Internet Protocol (IP). “SIP”, follows the ASCII-format (an application layer protocol), used to initialize, maintain as well as end calls between the end-points.
“SIP” defines the address operation of the signaling and session management within a packet-switching network. The call information moves out of the network area through “signaling”, where as, the attributes of the end-points are controlled by “session management”. The working of “SIP”, is summarized below,
Interprets the location of the destination
Checks the availability of the destination, if not available, determines whether the target is busy on another call or not answering the call on continuous rings. If available then “SIP” establishes the session between end-points. The mid-call change, there is an addition of end-point creating a conference call is one of the features of “SIP”.
Once the communication ends, the call terminates from the destination.
Let us now get down knowing on “H.323 protocol” and exploring some of its features with respect to VoIP.

The “H.323 Protocol”

“H.323” a protocol standard, defined by “ITU-T”, works for Voip, it avails the facility of voice transmission along with data collaboration and video communication.
“H.323” architecture comprises of terminal, gatekeeper, gateway, Multi-point control unit (MCU).
Terminal is the end device for every connection, it setups a communication with other “H.323” terminal or MCU or gateway. Communication in terms of voice, video, data, that may be communicated independently as well in combinations.
Gateways, bridge connection of the “H.323” network with the terminals of different network. Gatekeeper, act as translator between IP addresses and telephone numbers. Managing the bandwidth and providing mechanism for authentication with terminal registration are also one of the tasks done by “gatekeepers”.
MCU’s, are mainly used for multipoint conferences. MCU consists of a mandatory point know as Multipoint control, which comes into picture when call signaling, multipoint processor and conference controls are used. Along with above mentioned features there is around five information exchange enabled in “H.323” architecture-
1. Controlling connections and sessions
2. Audio (voice) digitized
3. Video digitized
4. Communication control
5. Data
After the above discussion, the queries related to the technical working of VoIP would get solved. This would be especially helpful for users, using VoIP but are not familiar with the internal working of VoIP. Do let us know how it seems to know VoIP with such a close view. Get back soon.

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