Voice over Internet Protocol, also known as VoIP is the mode of delivery of voice data from one node to another node with using broadband, internet, IP enabled network as the channels of transfer. Normal public switch telephone networks use continuous data for the data transfer and thus they come at some good price to the consumers and they are analog by nature.

However, Voice over IP is a digital mode of communication, in which data is transmitted in packets sequentially known as quanta or discrete packets. Thus the great advantage they provide is that they come at near free price. The typical term of VoIP is derived from the organizational setup called as VoIP Forum, which was the joint venture of some operators – Cisco, 3com, Net Speak and Vocal Tec. When the transmission takes place through internet, they are done so by satellite and broadband transfers. When it comes to the transfer between IP enabled networks, they take place in intranet.

For assurance of timely delivery of the discrete data packets over the network, VoIP adopt RTP (real time protocol). However the QoS (Quality of Service) is still not very great as they telephonic voice transfers are, in most cases. In order to cope with that, many operators are adopting different supporting technologies which can do proper canalizations and noise-free quality voice transfer. However, the public service providers or operators are lesser capable than the private inter service providing networks.
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VoIP to VoIP communication, as we mentioned, is normally free for the patrons. However to establish communication through PSTN to VoIP, there are two alternative methods known as DID (Direct Inward Dialing) and there is this access numbers. In case of DID, there is direct connection attained between those two concerned nodes. However, in access numbers mode, the ISDN party has to provide the extension number of the VoIP network and for this reason, DID is bit pricey than access numbers.

With many developments surging ahead, there is also the availability of full fledged phone service over the VoIP accessed through DID method. Thus they provide incoming and outgoing facilities both and as it is less costly than the normal telephonic expenditures, they also give various extra facilities so as so that these are known as internet phone / broadband phones among most of the naïve users.

Several big companies tend to adopt Voice over IP among the users inside their wide area network or intranet, so that the collective cost to the company is marginally cheaper than other alternatives and only one circuit and bandwidth connection proves very cheaper for establishment of the network too. For long distance calls such as ISD calls, which are very costly, VoIP comes as savior as they are completely locality independent.

There has been lots of development going on and one can’t rule out the possibility of complete amalgamation of internet and telephonic kind of data and voice transfer in internet. IP multimedia subsystem (IMS) will play a vital role in development of these tentative models.

VoIP or Voice over Internet Protocol is a remarkable service for the users of the Internet as it allows them to make voice calls via Internet. The technology works on the broadband Internet connections and not on the conventional analog connections via phone lines. Some of the services let the users call anyone with a telephone connection. Whereas some services are restricted to the users of the same company. You can make calls on international, long distance, mobile and local numbers. A number of companies provide this facility over a computer or a VoIP phone and some even allow the calls to be made via a traditional phone which has been connected with a VoIP adapter.The basic requirement for using this service is to have a broadband connection which can be through DSL, cable modem or a local area connection. The signal is converted to a regular phone number if a traditional phone is being used and even wireless “hot spots” in places like parks, cafes and airports can be used to connect to the net and make calls. Normally, the VoIP providers let you make calls to the users of the same service for free and a fee is charged if calls are made to another service provider. Depending on the provider, you can pay a fixed flat sum for calls made outside the circle or you will have to pay regular wireless phone charges. The most striking feature of VoIP is that the Internet connection can be used simultaneously while making calls in most of the cases.

There are a number of features available with VoIP that are making it a favorite among the Internet users of today. It lets you to make calls on the go making it a useful mobile service. Features like call forwarding, caller ID, call conferencing and voice mail make it a great option for your communication needs. Some providers might even give you the facility of unlimited long distance calls, bypass taxes and even value added services like integration with software. The fact that calls made using this service are 30 to 90% cheaper than normal telephone calls which make it an irresistible tool to work with.

You can even combine audio, video and data applications together. It means that you can combine the functions of your fax, Email, web discussion and video phone together with your computer. Such a service spells better organization and saves money and time for the user. You can even make your own area codes allowing you to club your friends and family in one regional code, letting you make calls to them for a fraction of the3 cost it would otherwise take. It is a flexible service as you can make calls from anywhere you go by using the Internet. You can use it while living in a hotel, visiting a café and even in your office! As most of the extra functions are provided free of charge, you can enjoy call block facility, caller ID, call forwarding and conferencing at no cost at all. With all the features of VoIP, there is no reason why one should not give it a try.

VOIP is a next generation technology through which telephone calls can be made by using the computer network, over a network such as the internet. In VOIP service the voice signal gets transmitted as a digital signal and again converts back to the same as we talk over a normal phone.  VOIP   calls can be made with a phone attached to a adapter. A dial tone is heard every time a call is made through a VOIP service. A VOIP call is made directly from a PC to another PC, using a microphone.

Internet protocols are generally network servers and switches and the software being installed can easily be upgraded and modified even after ten years from now. Since the maintenance cost is almost zero, where the up gradation is made without any extra charge. In this way the system remains refreshed and even after years it will seem like new.
A user firstly determines the quality of the service, so that an important call is never missed VOIP requires a vast network for the betterment of the call quality.  If the coverage is not good in the home circle then the consumer can fix the problem or get used to it. The same fault would not be tolerated in the guest room by the business tycoons.
The VOIP is such a network that even works in a heterogeneous environment.

Voice calls should have such capability that it can carried by any local networks. Like the PBXs, PSTN, and the internet. Advancement in the VOIP software means PC telephony software is available with every software developer.
The traditional PSTN telephone structures i among the masses for the last hundred years and has established itself as the most reliable voice communication system. Where as VOIP is a new technology in which people will depend but in a slow progress as it need some time to establish itself in the market.

As VOIP is the latest technology in the market it can become the cause of many developments in the society, like the recognition of speech, synthesis of speech, and digitized audio is among the popular one commonly used in call centre activities. Cinema tickets can also be booked through VOIP.
Wireless VOIP is the latest development in the society. But the main focus remained i the implementation of Wi-Fi that is based on software named IEEE 802.11 WIRELESS STANDARD. The main benefit is to replace the expensive mobile phones with the cost effective internet based calls. Once the VOIP gets logged in to the network, one can easily access their normal phone extension, and one can also enjoy all its features and functions sitting anywhere away from the actual location.

VOIP wireless can be run in a number of ways, such as software can be loaded in the laptop and can be used easily in a WiFi zone. This wireless technology has got already established in the market, and the soft phones or the software phones are also available for handheld computers and PDAs. Nowadays Wi-Fi phones are in the markets which are similar to the mobile phone, which uses a wireless internet connection.

Thus VOIP is a new step towards various dimensional reality of life.

Voice-Over Internet Protocol even termed as VOIP, Internet telephony is the steering of call conversations through the IP-related network or other Internet.  Companies, which provide VOIP services, are called providers and protocols or certain rules are used to execute the voice signals is called VOIP protocols or Voice over IP. This can be viewed as commercial achievements or exploitation from Network Voice Protocol designed for the ARPANET providers.

The steady and increased use of Internet usage has resulted in immune prospective for “VOIP service providers”. VOIP is directed to transmit voice in data form or information through the Internet to increase the efficiency and reduce call costs. The equipments required for transmitting the voice over Internet is also not too high, so it contributes in making VOIP being the most reasonable telephony service. Another important aspect of VOIP is the mobility by which you can stay coherent with the world through the Internet. But, all that is needed is a PC or a VOIP phone.  VOIP may provide you with two types of services – Free or paid services. The Free services are usually availed when you are calling friends, family or other relatives. The paid services are used in case of business uses.  VOIP providers are omnipresent in plenty that makes the market for VOIP providers much more competitive. So, for the regular user, it becomes hard to choose the best provider. For that you need to analyze your needs or your business requirements. For invigilating the service, you can question providers for the “Average call duration”, “average success ratio” & “post duration delay” of the relevant call. The higher is the previous 2, & lower the latter one; it’s the best for the standard of the service.

 The different functions of VOIP are:

•    Transmission of more than one telephone call down the same broadband connected telephone line

•    VOIP is location independent; it just needs an Internet connection to the service provider.

•    VOIP services can integrate and work with other services working over the Internet like video conversation, data file exchange, audio conference etc.

•    It is very reliable as well. VOIP hardware uses broadband modems and equipment powered services by household electricity that can be useful as outages in the absence of a generator.

•    As a single network is used, thus, the cost is a bit lower and they are used to carry voice and data. This can work more effectively when users have a spare or unutilized existing network capacity. So that network carries the VOIP at no separate cost and hence saves money overall.

•    VOIP to VOIP calls may be free but VOIP to public-switched telephone networks will cost you money but still VOIP is the cheapest and most efficient telephony service.

Some Challenges faced by VOIP are:

•    Sending fax is still a problem with VOIP. The support of sending fax over VOPI is still a bit short of options.

•    Delay/ Network Latency

•    Jitter

•    Echo

•    Packet Loss