IP telephony is a telephone system that allows us to make phone calls using the internet instead of traditional phone lines. This technology has become trending, providing features such as video calling, conference calling, etc, at a cheaper rate than traditional phone lines.

Today, we will be discussing what is IP telephony and understand its working mechanism. So, follow along to learn about the following concept in a crystal clear manner.

What Is IP Telephony?

What Is IP Telephony

IP Telephony, also known as Internet protocol telephony, is a technology that allows us to send and receive voice data via the Internet. 

IP telephony was first evolved in 1995 and has been contributing to the telephone industry ever since with its wide range of features and benefits. 

Landlines and cell phones transmit analog signals, whereas IP phones connect to the internet through a router and modem. IP or Internet Protocol addresses are used for computers and devices to communicate with each other via the Internet.

You don’t need costly hardware to install IP Telephony. Only a stable internet connection and a one-time download of any IP telephony app is required. This saves your time and regular maintenance costs. 

For example, Skype, Viber, WhatsApp, and Facebook Messenger are some applications that employ IP Telephony. It allows you to make and receive calls for free through the Internet.

Key Components of IP Telephony Systems

Key Components of IP Telephony Systems

Several key components collectively come together to enable voice communications over Internet Protocols (IP) networks. The components are listed below.

1. IP Phones (Softphones)

IP Phones make use of the internet to transfer voice data but look similar to traditional phones. Analog voice signals are converted into digital packets and vice versa using IP phones. It provides features like call forwarding, call routing, and voicemail. 

Softphones are software-based replacements for traditional phones that operate on desktops and mobile phones. And it allows users to make and receive calls straight from their devices. 


IP PBX (Private Branch Exchange) can either be a software-based solution or a physical hardware. Instead of being dependent on analog lines, it uses the internet to transmit inbound and outbound calls as well as manage other communication aspects.

IP PBX is referred to as the central component and control unit of an IP Telephony system. It handles features like call processing, call routing, voicemail, call forwarding, Iterative Voice Response (IVR), etc.

3. VoIP Gateways

VoIP gateways act as intermediates to establish communication between traditional Public Switched Telephone Networks (PSTN) and IP telephones. VoIP establishes coherent communication between IP Phones and ordinary traditional phones. 

They convert analog signals to digital packets for IP transmission and vice versa.

4. Session Border Controllers (SBCs)

SBCs are employed in IP Telephony to protect the network from any unauthorized access and assaults. 

They act as gatekeepers checking credentials, not letting intruders in, and ensuring the conversation is private. This way, your VoIP calls will go smoothly and securely.

5. Switches and Routers

Switches and routers are essential devices to establish an internet connection. These devices successfully transfer voice packets across the IP network. 

The router chooses the ideal route for data to travel, while switches control data traffic in the network.

IP Telephony Protocols

IP Telephony depends on several open-source protocols to transport data from the device to the service provider. The aforementioned protocols enable numerous features of Voice over Internet Protocol to be accessible. Some important protocols are listed below.

1. SIP (Session Initiation Protocol)

SIP stands for Session Initiation Protocol. It is used to initiate, modify, and end real-time sessions between two or more participants, which involve audio, video, text, and other similar applications. 

SIP is similar to HTTP protocol as it is also text-based, and the request-response mechanism makes troubleshooting faster and easier. SIP protocol keeps up with the technological requirements of IP telephony.

2. RTP (Real-time Transport Protocol)

Real-Time Transport Protocol (RTP) transports standard packets of audio and video through IP networks in real-time. RTP is used in entertainment and communication systems such as telephones, video calling applications, and television services.

RTP efficiently cooperates with RTCP(Real-time Control Protocol) to make sure voice data is received on time on the other end and also resolves packet loss problems. 


Real-time Control Protocol (RTCP) RTCP is a companion protocol to RTP and is used to monitor the quality of service (QoS). 

And convey information about participants in a session. It provides feedback on packet loss, delay, and jitter.

4. H.323

H.323 is an ITU standard for multimedia communication over IP networks. It encompasses a suite of protocols and is used for real-time voice, video, and data communication.

While SIP has gained prominence, H.323 is still used in certain VoIP implementations.

5. SDP (Session Description Protocol)

SDP is used to describe multimedia sessions in a format understandable by both endpoints. It is often used in conjunction with SIP to negotiate session parameters.

How Does IP Telephony Work?

IP is a broad term for the technologies that allow telephone connection over the Internet by transmitting digital signals via Internet protocols. 

The protocol specifies how signals are supposed to move throughout the network. It defines the format, transmission, and display of data in web servers and web browsers, much like HTTP (HyperText Transfer Protocol). 

IP identifies speakers by scanning their analog voice signals, which it then converts into a digital version via the Public Switched Telephone Network (PSTN). 

Following conversion, digital signals are sent in a data format over a wide channel, rearranging a phone call. The data is then directed by signals via an IP system into the network and out so that the receiver’s web network can accept it.

To put it another way, IP telephony involves routing phone calls via an IP system and a cable into the network. Finally, into the internet connection after exiting. 

The entire system uses IP and LAN (Local area network) to transmit calls and other data over the office network and the provider’s network, replacing the traditional phone line and phone network. 

Benefits of IP Telephony

Benefits of IP Telephony

Unified Communications (UC) Network

Due to its dependable voice connectivity over LANs, IP telephony is widely recognized. It is also regarded as the unified communications (UC) model because of its dependability and many useful capabilities, including support for web, video, and audio conferencing.

With little financial investment, this unified communications solution will boost organizational growth.

Smart Mobility/ Connectivity Solution

Without any hesitation, IP telephony helps everyone communicate better—remote workers included. In today’s world, you do not have to go with a business phone that is prepaid. 

With IP telephony, remote workers can use their cell phones to access the network from any location with an internet connection. It enhances connectivity to other cities, countries, or even additional business stations. 

As a result, these mobility options are improving the working environment for employees.

Easy-to-use Softphones Technology

Softphones are simple to use and take only a few minutes to set up and start up. Without requiring any devices, you may just download the softphone software service to your desktop or laptop. 

Following that, you can use your laptop to make international calls. All UC (Unified Communication) services will be available to you as soon as you establish a connection with this service. 

Softphone technology provides an excellent digital calling experience and is integrated with a multitude of functions.

Features-Rich Communication Aspect

Due to its extensive feature set, IP telephony is, without any doubt, transforming communication methods. One such example is the fact that IP phones have the capability to do much more than just make calls. 

Teleconferencing capabilities, configurable buttons, auto-attendant functionality, voicemail-to-email transcription, etc., are some of its key features. 

IP phones can be used to replace traditional phone systems thanks to this feature set.

Easy to Install and Configure

The IP phones are easy to install and configure, even for people without technical backgrounds. Programming, proprietary software, graphical user interface, and other specialized knowledge are not necessary. 

In simple terms, it is easy enough for someone with no networking knowledge to install and configure.

Challenges of IP Telephony

Challenges of IP Telephony
  • Call Quality Issues: The situation of decrement in call quality arises because of various factors like network congestion, packet loss, and insufficient bandwidth.
  • Low Bandwidth: IP telephony relies on internet bandwidth thereby, inadequate bandwidth results in degraded call quality.
  • Security Issues: IP telephony is not fully secure to several security threats like eavesdropping, unauthorized access, and denial-of-service attacks.
  • Emergency Services Support: In the case of traditional phone systems, accurate location information of a caller for emergency services is accessible. With VoIP, the physical location of the caller isn’t that accurate, causing problems for emergency responders.
  • Power Failures:  VoIP phones highly depend on electricity to run, so they don’t work if there is a power failure. On the other hand, traditional phones work smoothly even if power disruptions occur. 
  • Skill Set and Training Requirements: Switching from traditional telephony to IP telephony demands a completely new skill set. And staff aren’t used to having such kind of expertise.
  • Network Dependency: The stability of the network matters a lot in IP telephony. Network issues or disturbances can hurt communication flow and business operations.
  • Compatibility issues: IP telephony has a high possibility of not being compatible with all devices, operating systems, or browsers.

How is IP Telephony different from VoIP?

IP Telephony is a big term that makes use of Internet Protocol (IP) to cover all kinds of voice communications. This includes both traditional telephone systems and the latest VoIP systems.

On the other side, VoIP (Voice over IP) is a communication technology that enables voice communication using the Internet Protocol. Although these two may sound similar they have a marginal difference between them.

You can also think of it this way: IP Telephony is one idea of talking on the phone with the use of the internet. Now, VoIP is also performing that same sequence of events but in a specific way.

To sum up, IP Telephony transmits voice communication using the Internet Protocol, whereas VoIP specifically refers to voice communication via the Internet. Hence, VoIP is a type of IP Telephony.


IP telephony, or Internet Protocol telephony, refers to all phone systems that transmit and receive voice data via an Internet connection. It provides advanced features like call routing, instant messaging, video conferencing, etc., without having to spend extra dollars on hardware.

IP telephony works differently from traditional phone calls. Traditional phone lines use the circuit-switching method for making calls. 

IP telephony uses a packet-switching method, which is much more reliable

and cost-effective. This is the reason why IP telephony is preferred over a regular landline or a mobile network.


What is an IP telephony system?

IP telephony system is any business phone system that utilizes VoIP technology to make and receive calls through the Internet.

What is the importance of IP telephony?

IP telephone systems are handy for managing conference calls, video calls, and other areas where the frequent streaming of audio and video is important. 

What does IP calling mean?

IP calling means when you make voice calls with the help of a broadband Internet connection rather than an analog phone line.

What do you mean by telephony?

Telephony refers to the technology that allows long-distance communication between two or more people. 

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