VoIP: The Internet Telephony

The journey of Telecommunications has been started back in 1876 with Alexander Graham Bell inventing the very first telegraph. It had passed through the number of revisions and evolved over a period of time. As far as I am able to recollect from my childhood, we had a typical touch-tone telephone.

Now it is the time of internet telephony. It is also known as VoIP.

What is VoIP?

Voice over Internet Protocol.

It is the exchange of voice and multimedia over the IP networks. It is built on the existing infrastructure of the internet.

Building Blocks of VoIP

Let us understand the basic building blocks of internet telephony. It consists of VoIP servers, trunk lines, clients, gateways, protocols & codec.

1.    VoIP Servers:

First thing first, the Server is any computer that provides services to other computers on the network. These are also known as IP PBX. Basically, it is similar to PSTN’s public exchange which routes the calls to the desired location. These are the data devices that transfer real-time audio communication.

As we are doing everything over the internet, the advantage of VoIP servers is that these servers need not be in the building. One can host these servers outside the premises like email servers. I just have to rent it.

2.    Trunk Lines:

Trunks are the shared communication path for a large number of telephone users. They resonate with the normal PSTN telephone lines. In the case of internet telephony, SIP trunks replace the physical connection with virtual connection over the existing IP network.

3.    VoIP Clients:

These are the end devices such as laptops, smartphones, tablets, and telephones. They are broadly categorized into two types namely

a)    Hard phones (These are pre-programmed, designed to provide dedicated voice only.)

b)   Softphones (These are computer devices made to act like phones using a piece of software.)

These clients connect to accounts within VoIP servers using the username and password. It is to authenticate, login and establish communication.

4.    Gateways:

The purpose of using the gateways is to convert VoIP communication into normal telephone calls or vice versa. The conversion can be from SIP to traditional, traditional to SIP. It significantly reduces the operational costs by connecting the legacy telephone system with SIP trunks.

5.    Protocols:

Protocols are the standard rules used to establish communication between devices over the network.

SIP (Session Initiation Protocol) is the common protocol used in VoIP. It is the application layer protocol used to create, modify and terminate the session over the internet protocol. It embodies the client-server architectures. The main advantage of SIP is that it is open source and can run on the TCP, UDP or other networking protocols.

6.    Codec:

The task of the codec is to encapsulate the voice or multimedia traffic into data packets and transmit it across the network. The codec will also determine the quality of voice or multimedia traffic and ultimately decides the amount of bandwidth required.

When it comes to internet telephony, latency and QoS are very critical. Any long delay in real-time communication is unacceptable. In a normal telephone call, the standard latency is defined to 45msec., whereas in internet telephony it is between 75-100msec.

Advantages of VoIP:

   The cost of VoIP is much cheaper than legacy telephones. It provides huge cost savings.

   It provides greater scalability to enterprise users.

   It is full of features like voicemail, queues, virtual extensions, call monitoring, call bridging.

   Better voice quality.

   It can be integrated with business applications such as outlook, emails.

Every six month the technology will double - Gordon Moore, Co-founder Intel

What's next?