What is VoIP?

You might have used services like Skype, Vonage, or WebEx. If not chances are high that you call to your friends now and then using WhatsApp, Viber or Hike. In case you’re wondering how you are able to make a free call to your friend over the Internet without using Cellular or Telephone service, worry not. This post will get your feet wet in what is known to be the most disruptive technology today called VoIP.

Tiny bit history

A little reflection recalls a time when Internet Service Providers (ISPs) transitioned to
high-speed options such as digital subscriber lines and cable. But your telephone was
still provided by the traditional local exchange carrier. With the greater capacity for data
connections, someone got the idea that it might be possible to run a telephone call over
an Internet Protocol (IP) based network. Our friends at Digium were one of the first to
point out that traditional providers would never have moved to improve services or
offerings were it not for the open-source community and the VoIP protocols.

Some of the first attempts included point-to-point connections or websites working as
the centralized call server. Calls like these were plagued by quality issues and a complete
lack of industry support. But the idea was out. And what an idea it was—free telephone
calls over the Internet? Sign me up! It was a golden dream for some (consumers) and a nightmare for others; namely, the providers. After all, telephone companies made a lot
of money without a whole lot of competition. It wasn’t long before services such as
Vonage, Skype, and Time Warner voice made their appearance. Some of these services
offered calling plans for less than half the price of traditional carriers. Some of them,
most notably Skype, had as one of their goals putting telephone companies out of busi‐

Meat of the matter

VoIP stands for Voice Over Internet Protocol. VoIP is a technology by which the voice (and video) is sent back and forth using TCP/IP across the data network. VoIP is also known by terms such as Internet Telephony, Computer Telephony, and even Windows Telephony. All you need is a high speed Internet connection and an adapter.

In order to understand VoIP let’s compare it with the traditional telephony system.

Traditional Telephony Topology

The traditional telephony system is a circuit switched network in which the bandwidth is allocated for a call throughout the length of the conversation. It’s a technology used for decades to provide reliable, low-bandwidth and high quality voice communication service. Typically in a traditional telephony system, the analog/digital phones connect to the local telephone exchange known technically as PBX (Private Branch Exchange). The PBX is responsible for establishing the calls using various control signals between the caller and the callee; plus maintaining the session and its eventual tear-down. All signalling is governed by the SS7 (Signalling system 7) protocol.

Basic VoIP Architecture

In VoIP, traditional telephones are replaced by the VoIP phones. Since VoIP phone is nothing but an intelligent application that supports VoIP protocols, a simple PC running a specialized application called softphone can be used as a VoIP phone. The VoIP phones connect to the Ethernet switch. An application named Call Server running on a server provides all the functionality of the telephone PBX, which is why it’s called IP PBX. All signalling and voice data are governed by TCP/IP.

As you can see, there’s not much difference in the functionality between traditional telephony and VoIP. However, everything underneath the architecture is completely different. Traditional telephony uses tip and ring, POTS (Plain Old Telephone Service), T-1 carriers, dial plan etc. governed by International Telecommunications Union. VoIP uses TCP/IP as its backbone and protocols such as UDP, SIP (Session Initiation Protocol), RTP (Real-time Transport Protocol) and codecs to covert voice to digital signals.

Why change to VoIP ?

Probably the biggest reason for adopting a VoIP-based architecture is money. Instead of paying for a series of telephone lines or circuits, customers need only pay for a data connection. This is because the VoIP traffic travels in IP packets that can share the data connection. In addition, IP packets can flow to any destination connected to the Internet, and toll charges are much reduced. There are several business cases in which forklift (removing everything in favor of the new equipment) changes to telephony infrastructure are justified based on the savings in toll charges alone. VoIP architectures can pay for themselves in a relatively short period of time, giving the company a good Return on Investment, or ROI.

There are several other, less obvious, opportunities to save money with an IP-based VoIP
solution. Networks deploying VoIP are often called converged networks because they share the data network. Once the data network is installed, all other devices are connected to it. This actually extends to other systems such as heating and cooling systems, security, and video cameras. The impact of this change is hard to overestimate:

• Single network to support
• Single set of devices
• Single set of maintenance requirements
• Single set of employee skills
• Many “off the shelf” components
• Single cable infrastructure
• Easier moves/adds/changes

All of these lead to a lower total cost of ownership, or TCO, for the network.

Employees using the VoIP endpoints may experience greater mobility if wireless phones
are supported, but softphones and the ability to log into any phone may also increase
mobility and productivity.

Unified Communications (UC), the cousin of VoIP also presents tremendous opportunities to realize improvements through integration of applications. UC systems are built upon a VoIP core, but, unlike VoIP, the case for UC is not always made through cost savings but productivity gains. The ability to collaborate, indicate presence, and use a single platform for
email, messaging, and text can go a long way toward achieving these soft benefits.

A slice of butter

I guess you now have a I-kinda-get-the-idea feeling. Let’s listen what our buddy Jeremy has to say on VoIP.

About Deepak Devanand

Seeker of knowledge
This entry was posted in VoIP and tagged , , , , , , . Bookmark the permalink.

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