What is Voice Over IP?
Voice over IP, also known as VoIP, is a system of transferring voice communications to data packets that can be transmitted via a data network. It is used for telephone service and multimedia applications including voice over the internet protocol (VOIP), telephones, distance education classes, online video calls, and conferences. VoIP technology converts analog signals from voice into digital form by sampling it with a sampling rate of at least 8 kHz or 16 kHz before compression to reduce bandwidth or throughput requirements. In other words, Voice Over IP makes it possible for you to make calls from your computer’s modem without installing any hardware! All you need is an internet connection and your voice will come through as if you were on the phone.
VoIP systems are generally designed as a series of servers and gateways which take incoming calls from switches or routers, convert the analog voice signals to digital voice as it makes its way to the application server, and then routes those digital voice streams to the correct user’s phone. This might resemble a traditional phone system where a single port or number is transferred from one device to another. The term “Voice over IP” should not be confused with other similar terms such as “voice over broadband” which refers to the transmission of audio over existing data networks. In simple terms, Voice Over IP is a means by which audio can be transported over an existing data network such as the Internet.
The concept of “Packet Voice Communications” was first described in a technical paper presented by David L. Mills on April 28, 1971. A series of theoretical papers have been written since then on the subject of voice, that is, methods of encoding analog voice signals into digital signals and then transmitting these digital signals over packet networks. This topic has received considerable attention in Europe, particularly in France and Germany. The World Wide Web Consortium (W3C) formed a standard for Voice over IP called SIP which is designed to work on the Internet Protocol (IP).
Features of VoIP
The popularity of VoIP has continued to grow since its inception. Several factors contribute to its popularity. They are described below:
- The bandwidth requirements of voice calling are much less than the bandwidth requirements for data transmission, so VoIP can use existing data networks more efficiently than traditional telephony. This is one of the primary reasons why VOIP is so popular with computer users who have limited bandwidth on their Internet connection. Other people (like telemarketers) come across VoIP services like Bit Torrent Bit Voice because it lowers costs, especially for international calls.
- Contrary to the belief that most people only use their computers for surfing, chatting, and emailing it has become abundantly clear that most people spend a great deal of time out in public (like schools, offices, or public transportation). They want to be able to use this time for conveniently talking on the phone. Because of this growing need for VoIP, the companies that offered these services (like Vonage and Skype) were quick to grow and prosper.
- This is quite different from traditional telephony because it uses packet-switched networks which are more similar to the Internet than traditional switched telephone networks. This means that most carriers’ network call quality is dependent upon how much traffic they currently have on their network. However, with VoIP, there is no delay between calls due to congestion. On the Internet, however, packets can get delayed if they are traveling between too many networks.
- For VoIP to be effective, it must have a reliable network. If the network is not reliable, the quality of voice communications will suffer. The reliability can then be achieved through various techniques such as redundancy and load sharing among other things. A good example is a company that implements a VoIP system for its employees. If they have a reliable network, the employees will be able to communicate more effectively with their managers.
- From an infrastructure point of view, VoIP can be expensive or cheap. The network management that must be applied to provide this service is substantial. The cost to install hardware for multiple switches, routers, modems, and other equipment is high. A good example of this is the cost to deploy a VoIP system in the City of London. When considering how much it would cost to implement Voice over IP in New York City, experience has shown that many other business/consumer services are cheaper due to the amount of traffic on their networks. They would be more expensive due to the number of calls over the VoIP network. One should also consider the cost and complexity of switching and routing and maintaining VoIP PBX’s (Private Branch Exchange) and servers.
The advantages of this system are:
- The development of VoIP technology has had two major advantages over traditional telephony that has paved the way for its success. The first is that it eliminates the need for telephone equipment to transmit voice communications, which reduces the cost of communication. The second advantage of VoIP is that it allows communication with people who do not have telephone equipment by using computers connected to data networks.
- VoIP is typically implemented on an IP network, meaning it can easily run over both wired and wireless networks. Wireless communication requires special attention due to the delay present in wireless communication links, which may introduce echo in VoIP applications. Echo cancellation techniques are used to address this issue.
- The Wireless Ecosystem Forum (WEF) VoIP guidelines are an attempt to set standards for wireless implementation of VoIP. Several companies have introduced mobile VoIP services, allowing wireless subscribers to make calls over the Internet. These services are charged on a pay-per-use basis or metered. Recent years have seen the introduction of mobile apps which allow users to use their mobile phone as a handset for IP calls run on data networks, thus sidestepping traditional cellular networks completely, while still being able to call other users on their mobile phones while using standard IP data rates.
- VoIP is supported by nearly all web browsers and computer operating systems including Mac OS X, Windows, and Linux.