What is IP Telephony

IP telephony is a voice communication over the Internet, which allows you to conduct conversations and transmit information using the Internet. Work with this technology is aimed at reducing costs and increasing work efficiency. The introduction of IP telephony allows you to effectively manage the communication system, quickly integrate new applications (CRM), in a short time to expand the capabilities of the system depending on needs, without investing significant financial costs.

How does IP telephony work?

How does IP telephony work?

When you talk on the phone, your voice is digitized and converted to data packets that are transmitted over the Internet. The other party, upon receiving this information, reproduces your voice, which the interlocutor hears.

The general principle of operation of IP-telephony telephone gateways is as follows: the gateway receives a telephone signal, digitizes it, significantly compresses it, splits it into packets, and sends it to the destination network via the IP network. The definition and connection to the desired gateway takes place according to the routing table, which is populated via the Web interface or telnet. Changing / adding / deleting an IP address is possible at any time.

The most economical way to organize the removal of PBX capacity to branches (for example, connecting a central office with stores) is to use IP gateways. This solution allows you to refuse to pay for GTS subscriber lines and limit yourself to connecting the branch to a data network. If the branches are located in different cities, the cost of long-distance communication is also significantly reduced.

Another way to use IP gateways is to connect an IP telephony operator to the network. In this case, you can make calls to any PSTN phone numbers. The cost of the call will be significantly cheaper, since long-distance / international tariffs of IP-telephony operators are significantly lower than the tariffs of telephone service providers. Learn more about telephony system.

The important components of IP telephony:


It is a vital device connected to the IP-network and the telephone network (PBX / PSTN).

Functions of Gateway:

answering a calling PBX / PSTN caller
establishing a connection with a remote gateway
compressing, packetizing and restoring a voice (or fax signal)
establishing a connection with a called PBX / PSTN caller
Thus, a gateway or Gateway is a basic and integral part of the IP architecture Telephony directly connecting the telephone network to the IP network.
Gateways of different manufacturers differ in the way they connect to the telephone network, capacity, hardware platform, implemented codecs, interface and other characteristics. But they all perform the above functions, which are basic for IP-telephony technology.


It is an additional device that is connected only to the IP network and carries the entire logic of the IP telephony network.

Functions of GateKeeper:

authentication and authorization of the subscriber
distribution of calls between
billing gateways (as a rule, GateKeeper does not contain a complete billing program, but only a standards-based interface to third-party professional billing systems, as well as an API for the operator to develop its own billing program).
GateKeeper is required on any IP telephony network containing more than two gateways. In the first gateways (in the first host-based versions of VOCALTEC®, Vienna, etc.), the GateKeeper functions in their primitive form were performed by the gateway itself. With the development of technology and the growth of IP-telephony networks, GateKeeper functions were moved to a separate module.

Although for some manufacturers GateKeeper may physically be on the same system as the gateway, logically this is a stand-alone module.


It is an optional additional module of the IP-telephony network, connected only to the IP-network, used for remote configuration and support of other network devices-gateways and dispatchers.

Functions of Monitor:

Interface for remote configuration through the IP network of the parameters of gateways and dispatchers of the IP telephony network.
The monitor is a convenient means of configuring and administering the network. The first gateways simply used standard network applications. Later, in order to optimize the work, the manufacturers of IP-telephony equipment began to release their own applications for these purposes.

Find the difference between SIP telephony from IP and VoIP

If you have ever read about virtual PBX at least once, then you probably came across these terms. Therefore, to begin with, we will figure out what is the difference between SIP, IP-telephony and VoIP. This will help you not to get confused in the terminology and immediately understand how everything works.

Let’s start with the broadest concept – IP (Internet Protocol – “Internet Protocol”). We can say that this is “the beginning of all beginnings”, since it is the IP protocol that connected all the computer networks of the world to the global Internet. That is why each computer has its own unique IP address, which is needed for data exchange.

There is a technology for transmitting audio data over a network – it is called VoIP (Voice over IP – “Voice over Internet Protocol IP”). Thanks to it, we can exchange any data where there is a voice – make calls via the Internet, broadcast webinars or watch video from video surveillance cameras with sound.

IP-telephony is the common name for telephone communications over the Internet. This is part of VoIP, but it includes only calls and video communications over the network and nothing more. As the name implies, communication is due to the same IP protocol.Learn what is VoIP.

An even narrower concept is SIP telephony. If IP-telephony is the name of the technology as a whole, then SIP is only one of its varieties, the communication protocol. If we make a comparison, then they also relate to each other, like a laptop and ASUS.

What are the benefits of IP telephony?

Following are the important benefits of IP Telephony

Scalable Communication System

The advantage of IP telephony is that it allows you to quickly change the virtual PBX base: to include or exclude subscribers from it. Most of the functionality is implemented through the “cloud” technology.
Virtual PBX allows you to build an office structure, regardless of the size of the business. At the same time, digital communication systems make it possible to use virtual data exchange channels within a single network of branches, which eliminates the need to install equipment in all offices and branches.

Reduced communication costs

According to studies, the reduction in communication costs after the introduction of IP-telephony can reach 45-80%, depending on the goals and objectives facing the system.

Best High quality of communication

The quality of communication is much higher than analog lines. When using IP-telephony you get the digital quality of long-distance and international calls.

Ease of Data Management

IP and traditional telephony are distinguished by the fact that the first allows you to access any statistics, establish the framework for spending money. You can set restrictions on either outgoing connection with particular subscribers. Most hardware IP phones use sip protocols because they work independently of a PC. The benefits of IP telephony make it easy to connect, and for this you do not need to lay additional lines. In addition, the low cost of IP telephony is also provided due to the features of the channel.

Unlimited Numbers of Connections

It provides connection to an unlimited number of analog and ip telephony operators, with automatic or manual [at the request of the subscriber] selection of the cheapest / highest-quality operator depending on the direction of communication / caller number / time of day / moon phase, etc.

Versatility and Scalability

Through 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 the appropriate equipment) to connect the subscribers of analog, digital and ip telephony.