2004
VoIP (Voice Over IP or Voice
Over Internet)
By Pawas Verma
Voice over Internet Protocol (VoIP) is a
multimedia technology where the broadband network is used for both voice and
Internet transmission. This allows people to make cheap voice calls over a
high-speed Internet connection using a special "IP" phone or a conventional
phone-set attached to an adapter. The advantage of this technology is that the
voice communications can ride along with Internet and other broadband traffic
without impacting too much on the capacity of the network or the cost of
providing services.
The bandwidth occupied by a voice message is a tiny fraction (0.3% of a DSL
connection to a residence OR 0.003% of a business connection) of the total
bandwidth of a connection. First, voice (in analogue form) is digitized, coded
and arranged into small information packets. These packets (packages) are then
mixed and multiplexed with packets of other information traffic like Internet,
data and video before transmitting to a distant location. Each information
packet has its own identification (Header and Destination bits). The destination
bits guide these packets on the network to a correct destination and the "Header
Bits" allow them to be identified, separated and regrouped to pass through a
decoder. The output of the decoder is filtered and amplified to regenerate the
original voice at the receiving end.
It is a great development from users viewpoint. A VoIP user can continue to use
his/her current telephone number or get a new VoIP number. The telephone number
is not fixed to one location. The telephone set and the telephone number can
move with the user. People can reach a person even if he or she is not at its
location. Similarly, a person can call on their phone from anywhere in the world
(in approved areas/regions) without incurring long distance charges. For a fixed
monthly fee, VoIP service allows limited or unlimited local and long distance
calling. For example, one of the biggest North American VOIP companies - "Vonage",
under its basic residential plan charges $19.95 per month for 500 minutes of
local and long distance calling. Primus Canada charges $14.95 for local
residential services which is lower than $25 - $35 per month charged by a
telephone company (based on a conventional telephone network ) for similar
services. One can also have local telephone numbers at different locations
(theoretically) in the same or different countries. In such cases, the area
codes could be either the existing ones or IP assigned area codes. A few
Canadian cable and telephone companies (Telus, Bell Canada, etc.) have started
providing VoIP services.
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