How Does VoIP Work?
To use VoIP your voice needs to be converted into digital data. Your voice is sampled – the sound is divided into discrete steps that are assigned a number value. This data is compressed and sent over the Internet, in packets of 1500 bytes. These packets contain information about their origin and destination. They also have a timestamp, which helps them to be reconstructed in the right order. The packets are converted from digital data to sound once they arrive at their destination.
Just like any other data that is sent over the Internet, VoIP data also contains a payload and information that determines where and how the payload will be delivered. In VoIP this payload is voice data. The packet also contains other information that helps fast delivery. This allows real time conversations over the Internet.
The Internet Protocol Suite consists of two physical layers - the data link layer and the physical layer. In VoIP the Ethernet is used as the data link layer. This allows reliable transmission of data by controlling and synchronizing the flow. The purpose of the physical layer is to act as a channel through which information is passed to the data link layer. Twisted pair cables are used as physical layers in VoIP systems. All network cards, routers, modems, Analog Telephone Adaptors (ATAs) and IP phones are linked to each other through these cables.
Sound signals from the user end are converted to voice packets. These packets are generated via sound cards. After the voice has been converted to digital equivalent, the audio stream is compressed by the VoIP software to enable quick and efficient transmission. The compressed data packets contain all the data required to reach the other end. Thus the quantized data intelligently finds its way through your modem and a maze of twisted cables to the other end of the communication channel.
The data packets may have to navigate through variable paths to reach the intended destination. This is due to the transient nature of web traffic. Once the data packets arrive at the listening end they are arranged in the order in which they were sent and the process of demodulation begins. Here they are converted to some analog equivalent which can be perceived by the listener. The delay or ping time between data transmission and reception must be less than half a second irrespective of their locations.
Broadband connection is necessary to communicate over VoIP without noticeable delays. This does not pose any difficulty because increasing number of web surfers are homing in on hi speed connections these days.
The data packets may have to navigate through variable paths to reach the intended destination. This is due to the transient nature of web traffic. Once the data packets arrive at the listening end they are arranged in the order in which they were sent and the process of demodulation begins. Here they are converted to some analog equivalent which can be perceived by the listener. The delay or ping time between data transmission and reception must be less than half a second irrespective of their locations.
Broadband connection is necessary to communicate over VoIP without noticeable delays. This does not pose any difficulty because increasing number of web surfers are homing in on hi speed connections these days.