What Is Voice over IP | VoIP | Part 1
Voice over IP (VoIP) – Definition
Voice over IP (Voice through Internet protocol) VoIP stands, is a technology that makes possible a telephone conversation using an Internet connection or other dedicated network that uses the IP protocol. More specifically with VoIP is the sum of application layer communication protocols that enable such communication. With many VoIP providers can also make calls to traditional telephone network (PSTN). The main advantage of this technology is that it eliminates the requirement to restrict the bandwidth for each call (circuit switched), using dynamic allocation of resources, characteristic of the IP protocols (packet switched). Are routed over the network data packets containing the voice information, encoded in digital form, and then only when necessary, ie when one is speaking of connected users.
Among other advantages over traditional telephony include:
- Lower cost per call, especially over long distances;
- Lower infrastructure costs, when it became available any I. P. network infrastructure is required;
- New advanced features;
- Implementation of future options does not require hardware replacement.
VoIP conversations need not travel on the Internet, but can also be used as a means of transmission any private network based on IP protocol, such as a LAN within a building or group of buildings. The protocols used to encode and transmit the VoIP conversations are often referred to as Voice over IP protocols.
One of the advantages of this technology is that it allows leveraging existing network resources, enabling significant cost reductions in both the private and corporate, especially in communication costs and inter-company between different locations. A corporate network, it can also be used for voice communications, enabling easier installation and support and increase the degree of integration of offices located throughout the territory, but connected via the network infrastructure. The private consumer, using a broadband Internet connection (high speed, always-on) can make and receive phone calls, relying on very cheap rates, especially for international calls.
VoIP technology also introduces new possibilities for offering telephone service, such as eliminating the distinction between local calls and long distance, maintaining different phone numbers on a single link, save voice messages on your computer, and allow completely free calls between users the same supplier.
VoIP is used by large groups and telephone companies:
- Protection of voice calls against eavesdropping
- Open problems
- Other issues and proposed solutions
- VoIP Protocols
- Mass market telephony over high-speed internet connections
- Voice over IP analog and ISDN connection
Use of VoIP by large groups and telephone companies
To date, VoIP installations in commercial buildings and residential buildings are few, while large corporations increasingly use IP telephony, creating dedicated telephone networks to link them to their seats, after conversion of the downstream stations switching into normal analog signals into IP packets and vice a versa for outbound communications. In this way, in fact, create a digital network within the group, which lends itself very well to be modified and adapted to provide the most diverse types of services.
This also reflects an emerging technology called Data Abstraction, whereby analysis of data transmitted on a line, you can deduce the characteristics of the device has established communication (e.g., the type of display, control buttons etc..) and configure the services made available in accordance with these characteristics. The call centers of large companies often use IP telephony for your use of the opportunities offered by this new technology.
Another advantage comes from being able to unify the type of connection and use optimally the available bandwidth. VoIP is also commonly used in the U.S. to route traffic to and from mobile national network PSTN (Public Switched Telephone Network).
VoIP is also widely used by telephone companies, especially on international routes. For users this usage is completely transparent in the sense that they do not realize that their calls are routed over an IP network instead of through the normal switching centers. There are many big and small companies which are using VoIP to cut costs of their domestic calls, routed through the data network that links offices and domestic premises. They also reduce the cost of calls to the outside carrying, net to the point closest to the central switch.
Some companies offer a gateway (literally way out) to connect a VoIP network to the normal PSTN. If you dial a normal phone number, the call is routed through the Internet to the company that manages the gateway, which will carry out the normal charge their cost. Sometimes the phone companies are also proprietary direct gateway, and thus achieve further savings.
Protection against wiretapping of voice calls
VoIP can offer a significant advantage for the protection of privacy. Indeed, in many implementations of VoIP, voice traffic travels directly between the terminals of the users and not through a central switching facility, which you can install a system of valves. However this is not always true, sometimes for technical reasons and sometimes for the pressures of the police managers on VoIP systems because they allow the interception of VoIP calls.
Furthermore, using an Internet connection can take a secure communications with asymmetric key cryptography and digital signatures that prevent third parties from intercepting the conversation and manipulate it (unless they hold a lot of computing power).
Open problems
IP networks do not have in itself no mechanism to ensure that data packets are received in the order they are transmitted or guarantee concerning the overall service quality. Current applications in the real world of VoIP you have to deal with issues related to problems of slow (basically it needs to reduce transit time and data processing during conversations) and data integrity (to prevent loss and damage information contained in the packages).
The basic problem of VoIP is the correct reconstruction of data packets received, given the fact that during the transmission can change the sequence of packages and some packages may have suffered loss or damage of the information, and so to ensure that the audio streams (audio stream) maintains the proper time consistency. Another important problem is keeping the latency low enough package, so you should not wait too long for the answers during the conversation.
The use of VoIP enables a charging call that is independent of the length (flat-rate Internet) and, if the recipient is a computer, from a place called (local or international). Therefore constitutes a substantial savings for utilities and telephone companies for the same when they bind (and pay), proprietary networks of other operators.
Continued…
