Describing what is VoIP along with Its Network Components.

What is VoIP?

VoIP stands for Voice Over IP. It is a relatively new communication technology that enables making and receiving voice calls over the existing packet-based Internet Protocol(IP) network.

To make a voice call using VoIP, a device should connect to the IP network with a microphone and speakers. Your laptop or phone is one of the examples of a device that may use VoIP for voice calls. There could be a video call also possible from a VoIP phone.

What is VoIP diagram

There are many software application examples of VoIP clients you may be using for newer IP-based telephony. E.g., making a voice call using Facebook or Skype from a phone or desktop is an example of a VoIP call. The client software uses the Internet connection for making and receiving voice calls over the Internet Protocol.

Network components in VoIP technology:

VoIP Network Elements

To enable VoIP communication over the IP network. There are additional components that have been developed. The following is the list of network components for VoIP.

Soft or IP Phone as a VoIP client:

The software on a PC or on a mobile device to send or receive calls. There can be dedicated IP phone hardware also.


The IPPBX device is mainly used in call centers for bulk calling using SIP trunking. It is the hardware and software for VoIP.

VoIP to PSTN gateway:

The gateway does the bridging between traditional PSTN and VoIP networks.

VoIP proxy:

The VoIP proxy works as a router for VoIP signaling and media.

What do I need to use VoIP? 

To connect to a VoIP network, the first thing is the softphone.

A softphone can be real hardware that implements the actual protocols and applications for communication over an IP network. Or it can be the only software that can run on a mobile device or a PC. Skype, WhatsApp, etc., are examples of VoIP mobile apps. These apps use their respective servers. For desktops, X-Lite and other softphones are the options. These phones can work with a VoIP provider.

Next is the VoIP account from a VoIP service provider:

A VoIP connection provider issues a username, password, phone number, and server address. A softphone needs to configure the setting in the phone to use the service. After settings, the phone registers itself with the provider. The softphone connects and is ready to make and receive calls if all is fine.

To initiate a call, the phone user dials a number, as it dials on any gsm phone. The call reaches the server, and the outgoing route is decided from dialed digits. If the call is towards another VoIP number, the call uses only the internet. If the call is to a mobile or PSTN, then VoIP to GSM gateway comes on the way.

We can also understand how VoIP works with the example of Skype. Skype is the most common voice-over IP service across the globe. Someone must download and install Skype software on a PC or mobile device. To use the service requires creating an account on Skype. When a user signs in, the client registers to the Skype server, and the user sees its online status. A chat or a voice/video call can be started with a contact added.

Analog to VoIP converter :

VoIP to PSTN gateway :

VoIP Protocols:

In the communication world, nothing works without communication protocols. The following is a list of the most commonly used.






Example protocol stack in VoIP phone:

IP->UDP->SIP/RDP->VoIPPhone with GUI

VoIP Projects:


Asterisk is an open-source IP-PBX. Provides call center solutions for an organization. The software supports E1/T1 Bri/Pri and VoIP lines. In Asterisk, internal phones are configured as an extension. The external line could be VoIP or an E1/T SS7 BRI/PRI line.

An Open source project for developing VoIP applications in the Browser.