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Справочник VoIP.
Billing System
The software product usually integrated with system of IP-telephony intended for the accounting, terrifying, the analyzing of charges and formed accounts for telephone conversations.
Codec COmpression/DECompression.
The general term used in digital processing of audio and video - algorithm of compression and decompression of voice, allowing to narrow a passband at transfer of voice. In IP-telephony codecs G.723 and G.729 are often used. Algorithms of codecs are certain in standard H.323.
H.323
The standard approved by the International Advice on Telecommunication in 1996. Formulates technical requirements for transfer audio- and video data through networks of data transmission and includes standards on video codec, on voice codec, on popular appendices, on management of calls and system.
G.711
One of basic components of H.323, the audio-codec, 3.1 KHz on 48, 56 and 64 Kb/s which supporting is obligatory for all final devices H.323.
G.723
One of basic components of H.323, the audio-codec for 5.3 и 6.3 KBt/s.
G.729
One of basic components of H.323, the audio-codec for 8 Kb/s
Gateway
Technically the sluice is an electronic repeater or the device that intercepts, transforming and directing electric signals from one network to another. The sluice is the basic and an integral part of architecture of the IP-telephony, directly connecting a telephone system with network IP.
Gatekeeper
The additional device, connected only to IP-network and bearing in all logical work of network of IP-telephony. Carries out functions autentification and authorizations of the subscriber, distribution of calls between sluices and billing function.
Internet
The international association of computer networks in which users of the personal computer, at presence of access rights, can receive the information from any other computer in a network. Originally, the network (namely its basic reports TCP/IP), has been developed in Advanced Research Projects Agency - ARPA at the American government for militaries in 1969. Earlier, has been named Arpanet. Then it has been demilitarized and transferred in commercial operation. In this period it was essentially improved. One of the most known, but not unique improvements - technology WWW (World Wide Web), developed in 1991 in institute CERN. The technology became so successful, that often in use under the Internet mean WWW.
IP Telephony - Voice over IP (VoIP)
Also well known as Internet Telephony or Technology of a voice transfer over IP Voice over IP - VoIP. Uses the Internet protocol (IP, see TCP/IP) for the organization of bilateral voice communication. IP - telephony provides connections between phones of users Also well known as Internet Telephony or Technology of a voice transfer over IP Voice over IP - VoIP. Uses the Internet protocol (IP, see TCP/IP) for the organization of bilateral voice communication. IP - telephony provides connections between phones of users if present corresponding sluices with a telephone system, and also between IP terminals (for example - the multimedia personal computer) or IP - terminal and Public Switched Telephone Network (PSTN).
Internet Telephony Service Provider, ITSP
Provider, that gives services of IP-telephony.
International Telecommunications Unit, ITU
International organization - which is developing standards, that using in telecommunication. In particular, ITU standard H.323, which is used in IP-telephony, is approved. More detailed information about ITU - you can find on site http://www.itu.int.
Interactive Voice Response, IVR
Carries out functions of access to the removed computer system by means of the voice menu, the choice of options in which is carried out by a dialing of figures or their combinations on a telephone set. The computer system sounds the asked information, collecting the message from in advance written down fragments, or synthesizing the voice message by means of transformation the text-speech
Packet Switching
Means the organization of connections by breakdown the information on packages, their sending by a network of data transmission together with other streams of the information and restoration of the initial information on the reception end. The basic advantage of switching of packages - efficiency of use of channels with the fixed and limited strip. Lack - is impossibility to guarantee quality of service (QoS).
Personal Identification Number, PIN
Unique digital code for identification of the user, intended for authorization in the beginning of a session with a sluice of the Internet-telephony.
Public Switched Telephone Network, PSTN
Popular (public) telephone system. In the decisions of an IP-telephony, offering service of type of a call "phone-phone" sometimes the Internet-telephony (ITSP) is used as a network of access to services of operators.
Quality of service, QoS
It is ability of a network to provide better quality (service) for the certain kind of the network traffic with variable priorities and admissible from time to time delays. In particular, by transfer of voice messages, IP-packages "with a voice" can raise a priority, that will raise quality of service.
Router
The device, or in some cases the software on a computer, which defines a following point of a network in a direction of a point of purpose where packages will be directed. Usually, on a way to the addressee, packages pass through some points in which routers are established.
TCP/IP (Transmission Control Protocol/Internet Protocol)
The general name of family of the Internet protocols. TCP and IP - are most known from them. TCP guarantees, that each sent byte will reach the addressee lost-free. IP appropriates local IP addresses to physical network addresses, providing with that address space with which routers work. Also the family of protocols TCP/IP includes protocol Telnet, which allows the distanced terminals to be connected to distanced units (computers), system of domain addressing (Domain Name System- DNS) which allows users to be addressed to units of a network on a symbolical domain name instead of digital IP addresses, the protocol of transfer of files (File Transfer Protocol - FTP) which defines the mechanism of storage and transfer of files, and also the protocol of transfer of the hypertext (HyperText Transfer Protocol - HTTP) which allows to make an exchange transfer of the information on computers with WEB browsers.
ASR (Average Success Rate)
The size, allowing to judge quality of communication in the given direction. It is calculated under the formula (taken place sessions of communication/total of attempts)*100.
ACD (Average Call Duration)
Average call duration in minutes.
CDR (Call Duration Report)
Call duration report for the period of time.
The architecture of the IP-telephony network
The Network of the IP-telephony (according to recommendations ITU-T H.323) represents a set of the following devices connected on an IP-network:
gateway;
gatekeeper;
administration manager.
The architecture of the IP-telephony network represents connected Sluices on an IP-network in a telephone system, which gives the direct interface to the subscriber and carry out the coding, compression and pocketing voices/faxes and their restoration. All mechanism of interaction of sluices and the account is made by Dispatchers. For convenience removed configurations and administrations of a network the Monitor can be used. These three components at different manufacturers can refer to differently, but all of them carry out the functions generalized above.
The SLUICE - is the necessary device, connected to an IP-network and to a telephone system (PBX/PSTN).
Functions:
to answer to a call of causing subscriber PBX/PSTN;
an establishment of connection with the distanced sluice;
an establishment of connection with caused subscriber PBX/PSTN;
Compression, packing and restoration of a voice (or a fax-signal).
Thus the sluice, or Gateway, is the basic and an integral part of architecture of the IP-telephony, directly connecting telephone with the IP-network.
Sluices of different manufacturers differ in the way of connection to a telephone system, capacity, the hardware platform, the realized codecs, the interface and other characteristics. But, all of them carry out the set forth above functions, being base for technology of the IP-telephony. The dispatcher, or GateKeeper, is the additional device connected only to an IP-network and bearing in all logic of work of the IP-telephony. Its basic functions:
autentification and authorization of the subscriber;
distribution the calls between the sluices.
Billing - as a rule, the dispatcher doesn't conclude finished billing program in itself, only the interface based on standards to the professional systems of billing of the third manufacturers, and also API for development by the operator its own billing program.
The dispatcher is necessary in any network of the IP-telephony containing more than two sluices. In the first sluices (in the first host-based versions VocalTec, Vienna, etc.) functions of the dispatcher in their primitive kind were carried out by a sluice. With development of technology and growth of networks of an IP-telephony, the dispatcher functions have been born in the separate module. However, at some manufacturers the dispatcher can physically be on one system with a sluice, logically it is the independent module.
The monitor - the unessential, additional module of the IP-telephony network, connected only to an IP-network, used for distanced configurating and supporting of other network devices, sluices and dispatchers.
The monitor is convenient means for configurating and administrating of the network. In the first sluices, were simply used, purpose for this standard network appendices, such as pcAnywhere. Later, with a view of optimization of work, manufacturers of the equipment of the IP-telephony began to produce own appendices for these purposes.
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