What is IP telephony?

The Internet fundamentally changes our understanding of both telephony and methods of communication. IP telephony is a technology that brings together the advantages of telephony and the Internet. Until recently, circuit-switched networks (phone networks) and packet-switched networks (IP networks) existed almost independently of each other and were used for different purposes. Telephone networks were used only for voice transmission, and IP networks were used for data transmission. IP telephony technology connects these networks through a device called a gateway.

Gateway is a device that includes telephone lines on one side and an IP network (for example, the Internet) on the other side. The gateway serves as an interface between the user's device transmitting sound (phone, computer, etc.) and the Internet; it ensures the reception and conversion of data into a form convenient for sending over the Network (and reverse conversion).

During a conversation, voice signals are converted into compressed data packets. These data packets are then sent over the Internet to the other party. When the data packets reach the destination, they are decoded into the original voice signals.

How it all began?

Internet telephony uses the Internet to send an audio message between two or more computer users in real time. The very first Internet telephony software product that allows you to send voice messages over the network, VocalTec Internet Phone, was introduced by the Israeli company VocalTec in early 1995. For the first time, a user of a personal computer equipped with a sound card, a microphone and an Internet connection was able to conduct voice conversations with another similar user, no matter how far they were from each other. Majority software products from the same series, which appeared later, allow users to speak into a microphone and hear the interlocutor’s response through the speakers.

Before I was born, new opportunity attracted worldwide attention. The technology has steadily improved and has very quickly reached the point where voice communication is easily possible, and continues to evolve further. Many companies presented similar programs. At the same time, in many systems, along with the ability to exchange voice messages, the ability to correspond, send files during a conversation, exchange graphic images and video images has been added.

Types of communication via IP network

Computer - computer . This is the earliest and simplest method of IP telephony. To organize traffic transmission, the user purchases the necessary equipment and software, and also pays the provider for the operation of the communication channel. The advantage of this option is maximum cost savings. Disadvantage: minimal connection quality.
Telephone - telephone . The subscriber does not need any special equipment, just a regular telephone. Voice traffic is transmitted over an IP network, usually in a separate, expensive section. The devices that organize interaction are gateways, connected, on the one hand, to the public telephone network, and on the other, to the IP network. Voice communication in this mode, compared to the computer-to-computer option, is more expensive, but its quality is much higher and it is more convenient to use. The quality of communication is comparable to the quality of a regular telephone conversation, because The company uses dedicated communication channels. In order to use this service, you need to call the provider servicing the gateway, enter the code and number of the called subscriber from the telephone set and talk in the same way as with a regular telephone connection. All necessary call routing operations will be performed by the gateway.

Computer - phone . The end user does not require any additional equipment. It is enough to have a telephone with touch-tone dialing capabilities on hand. This is necessary so that, having reached the operator, you can enter your code in tone mode, and then the subscriber’s actions are no different from the usual. Most modern telephones, including payphones and Cell phones, this function is provided. If for some reason there is no such telephone, then a beeper can handle the dialing function or, in extreme cases, special program, which can be downloaded from the Internet.

Web phone . Another one new service- this is a call from a Web site that allows you to make a call by selecting a link to the name of the called subscriber from the Internet page or simply dialing the subscriber's phone number. This decision is aimed primarily at expanding e-commerce capabilities. WEB-phone allows Internet users to talk directly, for example, with a sales representative or a specialist technical support the company he is interested in. Establishing a telephone connection occurs in the usual, familiar way of dialing a number or by simply clicking on a link, which is, for example, the name of a company, the name of the called subscriber, etc. on the Internet page. In this case, the user does not need a second phone line or interruption of Internet service, you only need to download a small client software, which can usually be found on the same Web page, and which is installed automatically. On the other hand, a Web phone allows company representatives to answer questions, demonstrate Web pages, and transmit necessary information, thereby improving the quality of services provided.

Advantages and disadvantages of IP telephony

The main advantage of IP Telephony is the lower cost of long-distance and international calls compared to traditional telephony.
Another advantage is convenience. Some people, a growing number of whom, simply find it more convenient to make calls from a computer than to use a landline phone. It is possible that in the future, IP telephony will completely replace wired telephony, just as CDs replaced magnetic cassettes, and were subsequently replaced by MP3 players.

The main limiting factor to the large-scale implementation of IP telephony is the lack of mechanisms in the IP protocol to ensure guaranteed quality of services, which makes it not yet the most reliable transport for transmitting voice traffic. The IP protocol itself does not guarantee the delivery of packets, nor the time of their delivery, which causes problems such as “ragged voice” and simply failures in conversation. Today, these problems are being solved: standardization organizations are developing new protocols, manufacturers are releasing new equipment.
Another problem that manufacturers of Internet telephony systems have to solve is the lack of a unified standard for programs that provide communication. Currently, communication over an IP network is only possible if the same systems are used on both sides of the connection being established. For example, a VocalTec Internet Phone user cannot call a FreeTel user and vice versa. This problem arose because the very first Internet telephony programs used proprietary protocols to communicate with each other.

Video communication in computer networks

Until recently, video communication was the province of large corporations and science fiction films. Digital video cameras were too expensive, and communication speeds left much to be desired. Now the situation has changed, but even today video communication is a kind of luxury item, which does not detract from the convenience of this progressive type of interactive communication.
There are many programs for organizing video communication or video chat on the Internet, the most popular include the following:
*Skype
*ooVoo
* ICQ
* Mail.ru Agent
* Trillian
*Windows Live Messenger
*Yahoo! Messenger and others.

How to establish a video call?

The most important condition necessary for the implementation of video communication is the availability of an Internet access channel with sufficient bandwidth. The fact is that during a video communication session, not only voice data is transmitted, but also a video stream. Of course, before being sent to the Network, the transmitted information is compressed using special algorithms that provide multiple compression, however, despite this, the bandwidth requirements still remain quite high. It is generally believed that to ensure quality voice communication via the Internet, the “width” of the Internet access channel must be at least 64 Kbit/s; to ensure high-quality video communication, this figure will be at least twice as large.

Software issues
In addition to broadband Internet access, special software will be required to organize video communication. Such software can be an IM messenger like ICQ, Google Talk or any other aforementioned program that has a built-in video chat function. Unfortunately, the listed tools are incompatible with each other - an ICQ user will not be able to communicate with a Skype user. Basically, ordinary Windows user XP can use the NetMeeting program included with this operating system.
It should also be noted that despite big choice programs for organizing video communication or video chat, but not all of them are suitable for working in local network, since in order to work they need a server and an Internet access channel. They were developed to organize communication with remote points, and not to work in a local computer network. Firstly, not all networks have access to the Internet, and secondly, video communication through a remote server will create a fairly large flow of Internet traffic, and this is usually paid. In general, it is strange to contact a server located thousands of kilometers away in order to contact a neighbor behind the wall.
Of course, there are specialized packages and even hardware solutions for organizing video conferencing on a LAN, but their cost is too high for the average user and they are aimed primarily at companies.

Hardware

To organize a video call you need:
*
* Sound card
* Microphone

The most popular means of “capturing” images transmitted over the Internet is a web camera. In addition to webcams, there are other tools for organizing video communication - videophones. The videophone is a completely independent device that does not require connection to a computer. Such a gadget is connected to the TV using composite connectors; connection to the Internet is usually carried out using an Ethernet interface. You can “call” from a videophone either to the owner of a compatible videophone or to a computer with a webcam and installed Windows program NetMeeting.
However, videophones are quite exotic devices, aimed mainly at the corporate sector (this fact is reflected primarily in their price); Therefore, traditional webcams are of greatest interest to us.

When purchasing a webcam, you should pay attention to the version of the USB interface used. The USB 1.1 interface will provide video capture with parameters of 640 x 480 pixels at 15 frames per second. USB 2.0, featuring more throughput, will allow you to get 30 or more frames per second.
There is no point in focusing on the quantitative parameters of web cameras - almost all of them have a resolution of 640 x 480 (remember that a resolution of 320 x 240 is sufficient for video conferencing), as well as a built-in microphone.

It is not expensive
Using video communication is completely free, so those who want to use video communication will not have to spend money on purchasing this service; Only broadband Internet access will be subject to payment.
One-time costs will consist of the purchase of a webcam or videophone.
Owners of some laptop models will not have to spend any money at all - many of them are equipped with built-in web cameras.

Advantages and disadvantages of video communication

Among the advantages of computer video communication, we can mention the relatively low cost of operation compared to other communication systems existing today, their versatility, and comparative ease of use. During the work process, video communication (video conference) subscribers generally see images of the interlocutor and their own on their monitor screens, which is necessary for visual control of the established connection. The image is dynamically updated at a speed of up to 15-25 frames/s, depending on the speed (bandwidth) of the communication channel and the channel load. Participants for negotiations use miniature video cameras and microphones with fairly good characteristics.
Speech is digitized for transmission over a communication channel.
The main advantages of computer video communication are the possibilities collaboration with documents and integrated information (text, graphics, images received from video cameras, as well as remote start software applications on the interlocutor’s computer).
Thanks to video communication, the implementation of full-fledged remote offices is becoming more relevant than ever. Video communication with offices for meetings, operational briefings, and conversations with individual employees will be in great demand. It often happens that an important fifteen-minute meeting requires many hours of standing in traffic jams. Video communication solves these problems, saving money and allowing you to spend your working time as efficiently as possible. What can we say about the situation when it is necessary to organize a meeting of people from different parts of our vast country - then only savings on transportation costs can almost instantly recoup the costs of conducting a video communication session.
In addition to traditional business applications, such as quick meetings, support for telecomputers (homeworkers and mobile users), distance learning and personnel certification, video communication can be effectively used in many other situations. For example, when recruiting personnel (recruitment agencies, remote job interviews, etc.); remote medical and other consultations with experts; assessment of various types of damage and destruction ( Insurance companies); monitoring in case of emergencies and natural disasters; interaction between scientists when conducting scientific research, etc.
By and large, video communication is necessary wherever efficiency is required in analyzing the situation and making decisions, as well as joint work in the mode remote access. This is an indispensable tool in the work of companies with an extensive network of branches. Modern means Video communications provide opportunities for collaboration with data and various applications, including signing documents, and existing cryptographic protection tools allow you to maintain the confidentiality of the content of video communication sessions.

Video communication itself has no disadvantages as such. However, disadvantages arise as a result of using certain means for organizing video communication:
* high requirements for communication channel capacity;
* low quality Images;
* poor synchronization of image and sound;
* long delay transmissions, long reaction time when ordering to view a recording;
* difficulty of maintenance and others.

Skype

Let's consider one of the most popular programs for organizing audio and video communications on computer networks - Skype.

Skype was founded in 2003 by Niklas Zennström and Janus Friis.

Skype is a free proprietary software that provides free encrypted voice communication over the Internet between computers (VoIP), as well as paid services for communication with subscribers of the regular telephone network.

It is possible to organize a conference call (up to 25 subscribers, including the initiator), transfer text messages and files, as well as video communication (currently, when using a standard client - up to two subscribers, and when using plug-ins from third-party manufacturers, their number is limited only by bandwidth channel ability).

Services provided by Skype

Paid services
SkypeOut
SkypeOut allows you to make outgoing calls to landlines and mobile phones in most countries around the world. Payment is per minute.
Calls within Russia
Calls to toll free numbers(such as +1 800 in the USA) are free, and even users who have not paid for the SkypeOut service can use them.

SkypeIn
Allows you to receive phone calls from users of traditional telephone networks. In this case, the participant receives a telephone number. All incoming calls to this number will come to account Skype, and with a positive SkypeOut account, calls can be forwarded to any phone number. As a bonus to the phone number, Skype provides a free answering machine for the entire time you use the number.

Skype Voicemail
An answering machine that allows you to record incoming messages when the user is offline.

Free services
SkypeCast
Voice chats - allow you to communicate with a large number of Skype users at the same time, create rooms for communication based on interests. SkypeCast has been discontinued since September 1, 2008.

The 21st century is the century of new technologies, high speeds, and a huge amount of information. Today, both in business and in everyday life, innovative solutions are required to optimize activities. One of these is IP telephony - a modern method of communication, which is currently actively replacing analog telephony. What are the advantages of such a means of organizing telephone networks and who needs it? Let's figure this out.

IP telephony: what it is and how the technology works

The development of Internet technologies provided the impetus for the emergence of IP telephony. In 1991, American researcher John Walker created the NetFone program, which made it possible to exchange voice messages over the Internet. This development, in fact, was the first VoIP phone. VoIP (Voice over IP) is a technology that allows you to “transmit voice over the Internet.” To connect analog telephone networks with Internet networks, special gateways are used that make it possible to turn ordinary telephones into VoIP devices. An alternative could be a computer, mobile phone or tablet connected to the Internet with special software installed on them. If desired, you can also purchase SIP phones.

IP telephony services are in demand both in the office and at home. This type of communication makes it possible to send messages by fax, organize online conferences, and forward calls. In addition, the use of IP telephony services can significantly reduce the cost of long-distance and international calls.

Advantages of Internet telephony

The first issue that worries potential IP telephony users is the quality of communication. An important advantage of the technology is that the sound quality does not depend on the distance at which the interlocutors are located, which cannot be said about analog telephony. When using Internet telephony, there is no noise, echo or other unpleasant effects.

The second important advantage of IP telephony is the low cost of communication compared to analogue. In particular, the cost of international and long-distance calls is much lower, and calls within the corporate network are free - regardless of the geographical location of the company's offices. As for the price of IP phones, it is quite comparable to the cost of analog devices. However, as we have already noted, these may be in favor of installing software on appropriate gadgets connected to the Internet.

Among others benefits Internet telephony notes:

• opportunity quick start for business - almost instantaneous telephone installation of the office at low costs;
• reduction of staff who were indispensable when using analog PBX;
• employee mobility: no connection to a telephone, there is always the possibility quick setup forwarding to a mobile phone;
• the ability to program and configure IP telephony remotely, without calling a specialist.

Let's consider possibilities provided by Internet telephony:

• Integration. IP telephony can be integrated with other communication solutions, for example, with the 1C program, with the company’s website, with various Internet services and software.
• Multichannel number, thanks to which the company’s clients do not have to wait for a long time for connection. This number will never be busy! In addition, IP telephony providers provide call center services at very attractive prices.
• Voice menu(auto attendant) and smart forwarding.
• Possibility of organization video communication, conducting video presentations.
• Access to any statistical data as part of the use of telephone communications, control and quotas for off-duty calls and any calls from corporate numbers.
• Voice mail, email fax, blacklist, reporting and much more.

According to the International Telecommunication Union (ITU/ITU), in terms of telephone penetration, Russia is among the leading countries - in 6th place. And in terms of Internet penetration it ranks 71st. 55 out of 100 people use the Internet.

What equipment is needed to organize IP telephony in the office and at home?

As we noted earlier, to organize IP telephony in an office or at home, you first need to have an Internet connection. Moreover, the data transfer rate must be at least 512 Kbps in both directions. In this case you can use analog phone . To do this, you need to connect a special adapter (IP gateway), thanks to which a regular phone will turn into a device that works via the Internet. IP gateways are single-channel (for home and small offices) and multi-channel (for large companies).

You can organize IP telephony by purchasing a telephone SIP device (manufactured by AddPac, Cisco, D-Link, QTECH, RAD Data Communications).

And the third method is the so-called soft IP phone, which is special software (for example, YouMagic), installed on a computer, tablet, smartphone.

Thus, Internet telephony can be carried out as follows:

1. "Phone-phone". Analog telephones connected to an IP gateway transmit voice signals, which are converted into compressed data packets when transferred to the Network. These packets are sent over the Internet to the destination and are decoded back into analog voice signals at the output. In this case, a full-duplex conversation occurs (when both interlocutors can talk at the same time).
2. "Computer-phone". Those wishing to organize IP telephony can purchase special software from the provider, with the help of which it will be possible to make calls. This software can be installed on any device connected to the Internet - smartphone, tablet, computer. It does not matter what device the interlocutor uses - analog, SIP or mobile phone.
3. "WEB-phone". This way you can make calls directly from your browser. For example, a business owner can organize calls on his website using a special script called click2Dial. In order to call the operator, the client only needs to click on a special button on the website.

IP telephony providers: who is who

Global telecommunications companies are currently massively abandoning outdated classical telephony, trying to interest users in modern convenient Internet telephony technologies. Analog telephony is gradually being forced out of the market, but the number of implemented and used analog telephony systems is still significant. Nevertheless, the number of landline telephones in Russia is steadily declining: 40.1 million in 2008 versus 36.6 million in 2013. At the end of 2015, the total volume of analogue telephone services amounted to 221.7 billion rubles, and mobile communications- 644.9 billion rubles. For comparison: in 2014, the volume of the IP telephony market in Russia was around 17.1 billion rubles. In general, there are currently about 30 million IP telephony users in Russia.

In Russia, the first companies providing voice communication services over the IP protocol appeared about 20 years ago. Currently, the IP telephony market has more than 500 licensed participants. The turnover of IP services in Russia per year is more than $65,000,000. Of this, more than half of the market is long-distance and international communication services. Among the leaders are the companies Interregional TransitTelecom (MTT), Rostelecom, TTK.

Analysts believe that growth factors for the Internet telephony market in Russia remain the increase in the number of users of fixed and mobile Internet access, the growth in the activity of IP providers and the persistence of high tariffs for long-distance communications.

When choosing an IP telephony provider, experts recommend paying attention to the following factors:

• Safety. The operator has a reliable mechanism to prevent telephone fraud.
• The operator has its own telecommunications network.
• Competitive price. Compare the tariffs of different operators and choose the most acceptable ones: for business it is not recommended to choose too low rates for calls, since large operators offer VoIP resellers lower quality communications at a lower price.
• Check if it can this operator organize the “transfer” of existing analog numbers.

Tariffs: price matters

The cost of connecting to IP telephony will depend on the chosen type of communication organization. Thus, purchasing an IP gateway will cost 4,000–15,000 rubles. The purchase of a SIP device will cost a similar amount: 4,000–10,000 rubles. Plus, you need to take into account the cost of accessing the Network and maintaining equipment. The provider you contact for help connecting equipment or setting up a service will only charge you for directly outgoing calls.

The advantages of IP telephony are especially clearly visible in the example of long-distance and international tariffs. Let's look at average prices. So, calling from Moscow to St. Petersburg will cost 60 kopecks per minute, to Yekaterinburg? 61 kopecks/min., to Irkutsk – 1 rub./min., to Vladivostok – 1.5 rub./min.

The transition to IP telephony significantly reduces costs for international communications. If we talk about the CIS countries, a call to Belarus will cost 45.43 rubles/min, to Kazakhstan – 1.2 rubles/min. The cost of a call in the USA fluctuates around one and a half rubles per minute of conversation on average. At similar rates you can call to Europe: Germany - 0.7 rub./min., France - 0.8 rub./min., Italy - 0.4 rub./min. A call to China will cost 1 ruble per minute.

Thus, using IP telephony services, you have the opportunity to make a phone call without contacting city telephone networks or cellular communications, while using advanced functionality, as well as reducing communication costs.

As IP telephony evolves from additional service is gradually turning into a kind of basic service, which will soon become one of the components of a unified multi-service technology.

From analogue to digital

As is known, telephone networks initially worked with analog signals. The sound, converted into an electrical signal, was transmitted through a copper wire. In order for one physical channel to serve several subscribers at once, frequency multiplexing was used: the bandwidth was divided into several subchannels using frequency filters. However, the more subchannels there are in one physical channel, the narrower the bandwidth of each of the subchannels, which causes certain problems due to which the quality of communication deteriorates: crosstalk occurs, parallel conversations suddenly cut out, etc.

These problems were solved by moving to time multiplexing and digital data transmission technology. In this case, the channels are separated not by frequency, but by time; a fixed time interval (time slot) is used to transmit the signal of each of them.

Further development of networks for digital data transmission made it possible to abandon time multiplexing in favor of packet switching with connection establishment. Packet switching, together with the initially inherent asynchrony of information transmission, made it possible to optimize the use of the bandwidth of physical channels. The use of the IP protocol, in turn, made it possible to transmit information through dynamic routing of packets without establishing a connection. Each individual packet is transmitted without creating a “direct channel” across network nodes that are available at any given time.

Advantages of IP telephony

Traditional telephony technology assumes that an individual subchannel with a fixed bandwidth of 64 Kbit/s is used to connect two subscribers.

Each of the subchannels is used to communicate with one pair of subscribers. An important distinguishing feature of IP telephony is that the telecom operator uses non-dedicated subchannels for each pair of subscribers. Speech converted to a digital signal is compressed and broken into individual packets that are transmitted over an IP network. Thanks to the use of modern compression algorithms sound signal

, to transmit one conversation, a subchannel with a capacity of not 64, but only 12 Kbps is required. In addition, if there is a temporary absence of a useful signal in a conversation (that is, there is a pause), then the same subchannel can be used to transmit other data. It is the effective management of traffic of communication channels that allows IP telephony operators to offer long-distance and international communication services at significantly lower rates than operators using traditional telephony technologies.

IP telephony for end users Important factors that attract end users to IP telephony is the ease of use of the service and. The procedure for making a telephone call through an IP telephony operator to another city or abroad differs very little from the usual dialing of a number using “8”. Only one additional operation is added - a call to the telephone gateway of the IP telephony operator to enter the payment card number.

IP telephony provides the end user with a real opportunity to make long-distance and international calls at significantly lower costs than through the usual G8. Thus, a call to Western European countries using the service of not even the cheapest operator (for example, Zebra Telecom) will cost a little more than 3 rubles. per minute, while a minute of conversation with the same subscriber with access to an international line through a local telephone operator will cost more than 15 rubles.

IP telephony also has a number of additional benefits. In particular, through IP telephony operators you can make long-distance and international calls from landline phones that have blocked access through “8”, which is sometimes very important for those who live in rented apartments. It should also be mentioned that payment cards for IP telephony operators are a very effective tool for controlling costs. The invoice for a call over the long-distance telephone network arrives after the conversation has taken place, and often the subscriber is unpleasantly surprised by the amount indicated in it, whereas when making a call through an IP telephony operator by payment card, the subscriber is guaranteed not to spend an amount on a conversation that exceeds the card’s face value. In addition, in this case, payment for the used telecom operator services is made in advance, which allows you not to worry about timely payment of bills later.

IP telephony for organizations

If we consider the use of IP telephony in the corporate sector, then first of all it is worth noting that there are two different approaches to the implementation of this technology. One of them is a complete abandonment of traditional telephony; in this case, a local network is used as a channel to connect subscribers. The second approach, which is sometimes called evolutionary, involves, along with maintaining the traditional telephone infrastructure, the installation of new equipment that allows expanding the functionality of the enterprise's telecommunications system.

It should be noted that for corporate users, IP telephony is not only effective means optimization of costs for long-distance and international telephone conversations, but also presents the opportunity to implement qualitatively new services based on IP telephony technologies.

With the evolutionary option of transition to IP telephony technologies, voice communication services can be implemented not only through public telephone networks, but also directly through the Internet. For implementation this decision special hardware device(IP phone) connected directly to the company’s local network. In addition to establishing regular voice communication, this solution allows you to organize conference calls, as well as send fragments of conversations by email. There is also such an option for using IP telephony in the office as connecting to office PBX a special module that separates calls. This module allows you to automatically make long-distance and international calls through an IP telephony operator, and local calls through the city telephone network.

Using multiservice IP networks, you can create such complex services as call processing centers call centers, which are software and hardware systems that allow you to automatically process a significant number of incoming phone calls (for example, carry out statistical analysis during telephone voting ), as well as implement the delivery of outgoing voice messages to a large number of subscribers.

When building call centers, both traditional and IP-telephony technologies (Computer-Telephony Integration) are used, which makes it possible to integrate informational resources and provide fast access to databases and communication tools. The main area of ​​application of call centers is ensuring automation of work various services enterprises and the creation of a single information space for the purpose of effective use of CRM and ERP systems.

IP telephony today

Technology development

In just a few years, IP telephony technologies have evolved significantly, and the solutions common today are significantly different from previous ones. On the one hand, this is due to the development of hardware solutions, in particular the emergence of powerful backbone and transit routers and powerful high-speed telecommunication channels. On the other hand, one cannot help but note the emergence of such qualitatively new technologies as dynamic routing taking into account quality of service (QoS) in multiservice IP networks and the resource reservation protocol for monitoring the quality of service of transit routers (RSVP).

Currently, quality of service is one of the most pressing problems in IP telephony. For proper transmission of voice traffic, it is necessary to minimize time delays; the total delay in the IP telephony network should not exceed 50 ms. This factor is even more important than ensuring the delivery of all packets, since, thanks to the use of modern audio codecs and adaptive extrapolation, an IP telephony user is not always able to notice the deterioration in signal quality due to the loss of individual packets. In case of traffic delay, a very unpleasant effect of echo, “flanger”, etc. occurs. Modern equipment

for voice transmission over the IP protocol (VoIP) allows you to ensure priority for the transmission of voice traffic over the transmission of regular data, obtain acceptable quality of the audio signal with strong compression, effectively suppress echo and various noises. At the end of the 90s of the last century, one of the serious problems of ensuring high quality audio signals was caused by the fact that public channels were used to transmit voice traffic. Today, telecommunications operators specializing in the provision of IP telephony services use only dedicated channels with priority for voice traffic over data traffic, which guarantees high quality

speech transmission. In this case, several options for routing voice traffic are used for each of thousands of directions, and if any problems arise, the traffic is instantly redirected to other channels.

If we talk about the telecommunications services market in Moscow and St. Petersburg, then currently IP telephony is most popular among private users. Telephone and universal telecommunications cards (which can be used to pay for IP telephony services and dial-up Internet access) have long been a part of the lives of many active consumers of communication services.

Although today most operators offer private customers only one service - long-distance and international communications, it should be noted that the largest telecom operators are gradually expanding the range of services provided. In particular, it became possible to use the services of domestic IP telephony operators in other countries through automatic international roaming. In some cases, operators provide their subscribers with the opportunity to use communication cards to pay for additional services such as entertainment and information channels, dating services, etc.

The pace of development of IP telephony technologies in the corporate sector is still much lower. And despite the obvious benefits of reducing the cost of long-distance and international telephone calls, many managers are in no hurry to implement IP telephony in their departments, not wanting to invest in the purchase of additional equipment and modernization of the existing telecommunications infrastructure. However, today the leading operators operating in the telecommunications services market offer corporate clients very simple services, the implementation of which does not require significant investments. One of these services is the so-called corporate PIN code. The organization is issued a PIN code that can be used by several employees (even simultaneously) both inside and outside the office. In this case, communication between the client organization’s employees and the IP telephony operator is carried out through the city telephone network. To improve usability technical service The operator company can program an office PBX to automatically dial the operator's gateway number and identify users by PIN code or phone number.

A very popular service nowadays is a virtual PBX. Its essence lies in the fact that, via the Internet, the client’s phone is connected to the SoftPBX VoIP station installed on the operator’s technical site. The SoftPBX station acts as an office PBX, provides telephone communications within the organization, conference calls, call forwarding and servicing of all long-distance/international and local calls. Using SoftPBX, the “call to order” service can be implemented. By pressing just one button, a request is sent to the station, after which it begins to automatically dial the desired subscriber.

IP telephony can be an effective addition to CRM systems. For example, by automatically specific number incoming call the system can quickly provide the manager with information about the client, his contract and the history of interaction with the company. In addition, if necessary, you can write phone conversation, place this entry in a “personal file”, send it to another department of the company or to another employee, providing it with a text comment.

Prospects

As it develops, IP telephony is undergoing important qualitative changes: from an additional service it is gradually turning into a kind of basic service, which will soon become one of the components of multiservice technology. In the future, IP telephony will combine services such as high-speed Internet access, telephony, video transmission, Mobile Internet

etc.

Currently, two types of protocols for transmitting voice traffic are actively developing in the world. Firstly, this is the H.323 group, which originates from traditional telephone protocols, and secondly, protocols created on the basis of IP technologies in order to increase the “intelligence” of network services, such as SIP, MGCP, MEGACO. Russian operators

IP telephony most often uses protocols of the H.323 group. This is because this protocol was the first generally accepted standard for the industrial implementation of IP telephony. Many operators are in no hurry to destroy well-functioning interaction patterns between equipment, personnel and billing systems. As for Western European countries, the H.323 group protocols are also actively used there, although there is already a clear tendency to switch to more modern MGCP and MEGACO. This is due to the progressive development of Internet technologies and network infrastructure. SIP in this group is the most protocol, somewhat similar to HTTP and, therefore, more accessible to perception and understanding by the average IT specialist. SIP is good for use in intranets based on complex solutions from one manufacturer. At the same time, the external protocol in the network of a telecommunications operator for an enterprise, as a rule, will still remain either H.323 or MGCP/MEGACO.

Of course, in the field of IP telephony there are still many different problems, such as accounting for the use of technological resources, traffic routing, billing, calculating the cost of transport delays, etc.

As noted above, IP telephony is gradually ceasing to be just a service, but becoming one of the components of a solution for transmitting heterogeneous multimedia traffic using the TCP/IP protocol. And it is quite natural that the development of individual multimedia traffic management tools affects the entire system of packet data transmission technologies. In current conditions, IP telephony is the basis for the development and formation of tools for processing and transmitting multimedia traffic.

It should also be kept in mind that IP telephony is not just an alternative to regular telephony. The relevance of the development of IP telephony solutions is due not only to the possibility of reducing the cost of telephone conversations and Maintenance infrastructure (although this certainly matters). In a strategic plan, IP telephony is a unified technical platform that will combine solutions for data and voice transmission, as well as for processing and subsequent use of this information in all business processes. Thus, the development of IP telephony in a certain sense is a means of increasing labor productivity and business development.

In the foreseeable future, IP phones will no longer be analogues of conventional telephones. New generation CRM systems will be built on the basis of IP phones, corporate knowledge base systems will be created, and ultimately there will be an integration of all information services Email, video conferencing and telephony into a single communication service that can satisfy communication needs corporate client of any scale - from small and medium-sized enterprises to large corporations.

The advantages of IP telephony over conventional (analog) telephony are described here. In this case, we are talking not only about asterisk, but about any IP telephony systems: both paid and free. Disadvantages of IP telephony, see.

1. The main thing, of course, is cheapness. Compared to analogue telephony, IP telephony [long-distance/international] costs a penny (and if direct communication between two subscribers/offices is sufficient, subscription fee for telephone communication may be zero - subject to the availability of communication via a computer network/Internet).
2. Universality: via IP telephony you can (theoretically) connect any subscribers using a variety of protocols/technologies (for example, Skype with an IP phone, send SMS to a subscriber from icq, etc.). In addition, of course, it is possible (through appropriate equipment) to connect analogue, digital and IP telephony subscribers.
3. Flexibility:
   1. Forwarding calls under various conditions, depending on the time of day, caller number, non-response of the subscriber, and so on. Those. a subscriber can be constantly accessible [via his PBX number] to other subscribers, regardless of whether he is on site or away.
   2. Assignment of "short" numbers for any subscribers.
   3. Integration with computer and mobile phones: both a computer and a mobile (or landline) phone, smartphone/tablet, etc. can act as subscribers.
   4. Recording conversations: starting from recording the fact of a call from number to number and ending with recording ongoing conversations and/or listening to a conversation in real time.
   5. Connection to an unlimited number of analog and IP telephony operators, with automatic or manual [at the subscriber’s request] selection of the cheapest/high-quality operator depending on the direction of communication/caller number/time of day/moon phase, etc.
   6. The ability to combine any number of offices or points into one virtual telephone network, each of which can have any number of telephones, with free calls within the entire virtual network[if there is communication between all these points via a computer network or via the Internet].
   7. As part of 3.3, subscribers have access to the PBX from the Internet, which allows remote subscribers (outside the office, in another city or another country) to make and answer calls as if they were in the office (and for free, you only need the Internet!).
4. Working with faxes. Although IP telephony (in fact) does not improve, but rather even worsens the work with faxes (in the sense that a smaller % of faxes pass through IP telephony without problems), it does simplify the work with faxes, since it becomes possible to send and receive fax directly from your computer without converting the document to paper form(and/or receive faxes by e-mail).
5. Additional features, as a rule, not provided by analogue telephony (or extremely expensive):
   1. Call from the site
   2. Voice messages mails can be transmitted to the subscriber digitally (for example, in the form of an audio file by e-mail, a link on a website, etc.)
   3. Conference call with any number of participants
   4. Queues: the ability (mainly for call centers) to distribute many incoming calls among a small number of agents, with alerts about remaining wait time, promotional/informational messages, greetings, and so on.
   5. Voice menu / auto attendant, which includes both a greeting and the ability to make a choice (including voice!) of the desired department or indicate the subscriber number.
   6. Using the PBX as an alarm clock, business/birthday reminder, calculator, phone number directory, etc.
6. Mobility: unlike analog telephony, where the telephone number is “tied” to a specific telephone socket, in IP telephony the binding goes (in particular) to the IP address, which means that employees can move from office to office, from building to building, from office to office within the same computer network, with the same number and without any additional settings ATS. In addition, the ability to forward a call (clause 3.1) allows any employee to work remotely (from home, another city or another country) as if he were at his workplace.
7. Many PBXs (for example, asterisk) are completely free for any use (both home and commercial).
8. In the cheapest option, subscribers only need to have headphones and a microphone connected to the computer - many client software options are also free!
9. Access limitation:
   1. For internal subscribers: the ability to restrict/bar calls to certain communication directions, or select different telecom operators for different groups of subscribers, etc.
   2. For external subscribers: depending on the telephone number of the external subscriber, prohibition of dialing numbers of certain departments, the possibility (or impossibility) of additional dialing of an external (local/long-distance/international number) directly from the voice menu, etc.
   3. For any subscribers (optional) - restriction of access to certain functions PBX, for example call forwarding, call recording, listening to conversations in real time, and so on.
10. "Black list" of subscribers with the issuance of any message to them.
11. IP telephony is not limited to voice transmission only. It can transmit text messages, display [for example, via Jabber] the status of subscribers (away, talking, busy, ...), provide video communication and is quite capable of replacing tools such as skype (which, after being purchased by Microsoft, the quality of communication has deteriorated, especially corporate) .
12. The number of numbers on the PBX is unlimited, and the number of simultaneous conversations/calls supported by the PBX is limited only by the capacity of the installed equipment *.
13. Billing: starting from call statistics (including local ones) and ending with the generation of invoices that you can issue to those who use your PBX for calls (for example, tenant organizations or even your employees).
14. Call interception, call parking.
15. Calling subscribers/clients according to the list and issuing them a voice alert/notification, while it is possible to ensure feedback(using the voice menu) and collect information about the results of the call.

* also depends on the PBX itself, for example asterisk works stably for up to 1000 simultaneous calls.

Recently, more and more technical innovations have been appearing, and people do not have time to keep up with the constant changes in technology. Because of this, the communications market simultaneously offers both outdated and technically more advanced telephony technologies, the difference between which is vaguely understood by users. Let's look at what the characteristics are, what are the advantages of IP telephony, and what opportunities this system provides to the user.

This is what IP telephony provides in the office, its benefits and advantages over analog communication systems:

• reducing the cost of any kind of incoming or outgoing calls, especially for international and long-distance calls;
• high signal quality: clear sound, complete absence of voice delay, no echo;
• lack of the concept of “busy”. The great advantage of IP telephony is the almost unlimited number of lines used under one number. This quality has been enthusiastically embraced and is widely used in call centers and website support;
• integration abilities. You can easily add new devices, mobile phones, regular analog phones, etc. to a working IP network, but networks of earlier generations are not capable of this. In addition, networks can be easily combined into one network different enterprises, mounted on different equipment, using different software products;
• and probably the most important advantage: An IP telephony network can do everything that the Internet can. For communication systems, this means linking a number to a website, a customizable answering machine, intelligent forwarding, video conferencing, free unlimited calls within an organization, free choice of number and other delights of the information age.

To take a closer look at all the features and benefits of IP telephony digital communications, you need to understand the basis of its work. If telephone communications The previous generation used an analog data transmission system (with the help of amplifying devices, vibrations from one subscriber reached another), while IP communication is digital. It means that sound vibrations the speaker's voices are converted into computer language, and then, at the recipient, back to sound.

Analog communication can only be made more powerful, but with digital data a computer can do whatever it wants, and what it does with it depends on software and the programmer's imagination.

You can always consult with us about Internet communication functions, and we will be happy to help you create, install and configure IP telephony and bring your company to new level working with clients and staff!