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Noman Thursday, December 13, 2007 02:53 AM

VOIP (Voice over IP-Internet Protocol-)
 
VoIP
Voice over Internet Protocol (VoIP) is the family of technologies that allow IP networks to be used for voice applications, such as telephony, voice instant messaging, and teleconferencing. VoIP entails solutions at almost every layer of an IP network--from specialized voice applications (like Skype) all the way down to low-level quality measures that keep those applications running smoothly.
In this Article
The VoIP Technology
Why VoIP Now?
VoIP in Action
How IP Telephony Fits In
VoIP-Based Services
What's Next for VoIP?
Unless you've been sleeping under a very big rock for the last year, you've certainly heard the phrase "Voice over IP" uttered. Perhaps you've seen those hilarious Vonage commercials that feature painful and embarrassing accidents caught on tape, promising to let you dump your local phone company in order save big on your phone bill. You may also have seen the Cisco telephones that are curiously inserted in prime-time shows like 24.

What is all the hubbub about, anyway? Why, VoIP, of course! VoIP, the fabulous secret ingredient in Vonage, Skype, Cisco CallManager, and a host of other revolutionary technology products you may have already encountered on TV, in the news, or in person. But what makes these products so revolutionary? What is it about VoIP that is such a big deal?

The VoIP Technology
Voice over Internet Protocol is a family of technologies that enable voice communications using IP networks like the internet. Inventive developers and entrepreneurs have created an industry around VoIP technology in its many forms: desktop applications, telephone services, and corporate phone systems. VoIP is a core technology that drives everything from voice-chat software loaded on a desktop PC to Mac full-blown IP-based telecommunications networks in large corporations. To the Wall Street speculator, VoIP is a single technology investment with many revenue streams. To the enterprise network engineer, it's a way to simplify the corporate network and improve the telephony experience for users of the network. To the home user, it's a really cool way to save money on the old phone bill.

But how? What makes VoIP do all this awesome stuff? Read on.

Why VoIP Now?
The concept isn't actually that new: VoIP has been touted as a long-distance killer since the later 1990s, when goofy PC products like Internet Phone were starting to show up. But the promise of Voice over IP was lost in the shuffle of buggy applications and the slow-to-start broadband revolution. Without broadband connections, VoIP really isn't worthwhile. So early adopters of personal VoIP software like CUSeeMe and NetMeeting were sometimes frustrated by bad sound quality, and the first generation of VoIP products ultimately failed in the marketplace.

Fast forward to Fall 2005. Suddenly, everybody is talking about VoIP again. Why? There may be no greater reason than the sudden success of a freeware VoIP chat program called Skype

VoIP in Action
Skype is an instant messaging program that happens to have a peer-to-peer (modeled after Kazaa) global voice network at its disposal, so you can use it to call people on your buddy list using your PC or Mac. All you need is broadband, a microphone, and a pair speakers or headphones. Voice calling alone doesn't set Skype apart from other IM applications like AIM or Windows Messenger--they also support voice. But Skype supports voice calling in a way that those applications can only dream of: Skype works in almost any broadband-connected network environment, even networks with firewalls that often break other voice-chatting apps. Plus, Skype's variable-bitrate sound codec makes it less prone to sound quality issues than its predecessors. In a nutshell, Skype just works. Perhaps that's why Skype's official slogan is "Internet Telephony that Just Works."




The world has noticed. 150 million downloads later, Skype now offers the ability for its users to call regular phone numbers from their PCs, a feature known as SkypeOut. Skype also offers a voicemail service and can route incoming calls to a certain phone number right to a user's desktop PC. There's even a Skype API that allows Windows and Mac programmers to integrate the Skype client with other applications. Videoconferencing add-ons, Outlook integration, and personal answering machines are just some of the cool software folks have developed using the Skype API.

How IP Telephony Fits In
But Skype can't take all of the credit for the recent growth of Voice over IP. A number of enterprise telephone system vendors have heavily promoted what they call "IP telephony"--the art of building corporate phone systems using Ethernet devices and host-based servers instead of old-fashioned PBX chassis and legacy technology. Cisco Systems and Avaya were two of the earliest players in the VoIP-phone-system arena, and their stubborn support of IP-based voice technology is beginning to pay off. More and more corporate customers are integrating IP phones and servers, and upgrading their IP networks to support voice applications, interested primarily in the productivity boost and long-term cost savings of running a single converged network instead of maintaining legacy voice equipment. This transition is a lot like the move from mainframes and minicomputers to personal computers a generation ago.

On two fronts--the corporate phone system and that of the home user--VoIP is transforming the global communications matrix. Instead of two separate notions of a global network (one for voice calling and one for Internet Protocol), a single converged network is arising, carrying both voice and data with the same networking protocol, IP. Steadily, corporations and domestic phone subscribers are migrating their voice services from the old voice plane to the new one, and next-generation, IP-based phone companies have rushed in to help them make the move.

VoIP in Action
Skype is an instant messaging program that happens to have a peer-to-peer (modeled after Kazaa) global voice network at its disposal, so you can use it to call people on your buddy list using your PC or Mac. All you need is broadband, a microphone, and a pair speakers or headphones. Voice calling alone doesn't set Skype apart from other IM applications like AIM or Windows Messenger--they also support voice. But Skype supports voice calling in a way that those applications can only dream of: Skype works in almost any broadband-connected network environment, even networks with firewalls that often break other voice-chatting apps. Plus, Skype's variable-bitrate sound codec makes it less prone to sound quality issues than its predecessors. In a nutshell, Skype just works. Perhaps that's why Skype's official slogan is "Internet Telephony that Just Works."




The world has noticed. 150 million downloads later, Skype now offers the ability for its users to call regular phone numbers from their PCs, a feature known as SkypeOut. Skype also offers a voicemail service and can route incoming calls to a certain phone number right to a user's desktop PC. There's even a Skype API that allows Windows and Mac programmers to integrate the Skype client with other applications. Videoconferencing add-ons, Outlook integration, and personal answering machines are just some of the cool software folks have developed using the Skype API.

How IP Telephony Fits In
But Skype can't take all of the credit for the recent growth of Voice over IP. A number of enterprise telephone system vendors have heavily promoted what they call "IP telephony"--the art of building corporate phone systems using Ethernet devices and host-based servers instead of old-fashioned PBX chassis and legacy technology. Cisco Systems and Avaya were two of the earliest players in the VoIP-phone-system arena, and their stubborn support of IP-based voice technology is beginning to pay off. More and more corporate customers are integrating IP phones and servers, and upgrading their IP networks to support voice applications, interested primarily in the productivity boost and long-term cost savings of running a single converged network instead of maintaining legacy voice equipment. This transition is a lot like the move from mainframes and minicomputers to personal computers a generation ago.

On two fronts--the corporate phone system and that of the home user--VoIP is transforming the global communications matrix. Instead of two separate notions of a global network (one for voice calling and one for Internet Protocol), a single converged network is arising, carrying both voice and data with the same networking protocol, IP. Steadily, corporations and domestic phone subscribers are migrating their voice services from the old voice plane to the new one, and next-generation, IP-based phone companies have rushed in to help them make the move.



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How VoIP / Internet Voice Works
VoIP services convert your voice into a digital signal that travels over the Internet. If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination. VoIP can allow you to make a call directly from a computer, a special VoIP phone, or a traditional phone connected to a special adapter. In addition, wireless "hot spots" in locations such as airports, parks, and cafes allow you to connect to the Internet and may enable you to use VoIP service wirelessly.

What Kind of Equipment Do I Need?
A broadband (high speed Internet) connection is required. This can be through a cable modem, or high speed services such as DSL or a local area network. A computer, adaptor, or specialized phone is required. Some VoIP services only work over your computer or a special VoIP phone, while other services allow you to use a traditional phone connected to a VoIP adapter. If you use your computer, you will need some software and an inexpensive microphone. Special VoIP phones plug directly into your broadband connection and operate largely like a traditional telephone. If you use a telephone with a VoIP adapter, you'll be able to dial just as you always have, and the service provider may also provide a dial tone.

Is there a difference between making a Local Call and a Long Distance Call?

Some VoIP providers offer their services for free, normally only for calls to other subscribers to the service. Your VoIP provider may permit you to select an area code different from the area in which you live. It also means that people who call you may incur long distance charges depending on their area code and service.

Some VoIP providers charge for a long distance call to a number outside your calling area, similar to existing, traditional wireline telephone service. Other VoIP providers permit you to call anywhere at a flat rate for a fixed number of minutes.

If I have VoIP service, who can I call?
Depending upon your service, you might be limited only to other subscribers to the service, or you may be able to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. If you are calling someone who has a regular analog phone, that person does not need any special equipment to talk to you. Some VoIP services may allow you to speak with more than one person at a time.

What Are Some Advantages of VoIP?
Some VoIP services offer features and services that are not available with a traditional phone, or are available but only for an additional fee. You may also be able to avoid paying for both a broadband connection and a traditional telephone line.

What Are Some disadvantages of VoIP?
If you're considering replacing your traditional telephone service with VoIP, there are some possible differences:

Some VoIP services don't work during power outages and the service provider may not offer backup power.

Not all VoIP services connect directly to emergency services through 9-1-1. For additional information, see [url]www.voip911.gov[/url].

VoIP providers may or may not offer directory assistance/white page listings.

Can I use my Computer While I talk on the Phone?
In most cases, yes.

Can I Take My Phone Adapter with me When I Travel?
Some VoIP service providers offer services that can be used wherever a high speed Internet connection available. Using a VoIP service from a new location may impact your ability to connect directly to emergency services through 9-1-1. For additional information, see [url]www.voip911.gov[/url].

Does my Computer Have to be Turned on?
Only if your service requires you to make calls using your computer. All VoIP services require your broadband Internet connection to be active.

How Do I Know If I have a VoIP phone Call?
If you have a special VoIP phone or a regular telephone connected to a VoIP adapter, the phone will ring like a traditional telephone. If your VoIP service requires you to make calls using your computer, the software supplied by your service provider will alert you when you have an incoming call.

Does the FCC Regulate VoIP?
In June 2005 the FCC imposed 911 obligations on providers of “interconnected” VoIP services – VoIP services that allow users generally to make calls to and receive calls from the regular telephone network. You should know, however, that 911 calls using VoIP are handled differently than 911 calls using your regular telephone service. Please see our consumer fact sheet on VoIP and 911 services at [url]www.voip911.gov[/url] for complete information on these differences.

In addition, the FCC requires interconnected VoIP providers to comply with the Communications Assistance for Law Enforcement Act of 1994 (CALEA) and to contribute to the Universal Service Fund, which supports communications services in high-cost areas and for income-eligible telephone subscribers.

Aspects of these considerations may change with new developments in internet technology. You should always check with the VoIP service provider you choose to confirm any advantages and limitations to their service.

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regards
sincerely
Noman !


04:52 PM (GMT +5)

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