What is VoIP?

Posted by Jess Jepson on 14 February, 2015

Let’s start at the simplest level – an explanation of VoIP in the business environment (what is VoIP?)

Running separate voice and data networks presented many disadvantages for the modern business in the past. The inefficient usage of bandwidth, expensive maintenance of duplicate infrastructures and the high costs of telephone calls have rendered companies inefficient and uncompetitive with their global counterparts. Contrary to the belief that the biggest draw card for VoIP is the fact that companies benefit from lower call rates, there are other benefits that businesses are looking at with increasingly more attention.

With the convergence of voice, video and data on a single IP network companies now benefit from reduced administration costs by improving the ability to manage the network. In addition a converged network helps businesses to save procurement costs for network infrastructure. VoIP also allows the ability to improve basic telephony services by integrating it with data applications as companies strive to become more competitive. Applications such as unified messaging and virtual call centres help streamline operations and can improve a company’s ability to communicate.

The terms "VoIP" and "IP telephony" are often used interchangeably, but there is a difference. VoIP is the "packetization" of a voice stream for transport over an IP network. IP telephony is an application that provides telephony functionality (such as call connect, call forward, calling line identification) over an IP network, using VoIP to transport the traffic.

According to research from Gartner, in some countries, VoIP is treated as being equivalent to a regular circuit-switched telephone connection (for example ISDN2e or ISDN30e here in the UK), while in others, it is considered more as a data service.

What’s your perspective, and how would this impact on a company’s implementation of VoIP?

It all depends you see. Let me answer by explaining the difference between circuit switched telephone calls and VoIP. Circuit switched voice calls are transmitted over a PSTN (Public Switched Telephone Network). The speed with which voice is transmitted is an aggregate rate of 64 Kbps. A direct connection between two connection points provides a permanent 64-Kbps link for the duration of the call. This link cannot be used for any other purpose during this time. PSTN provides low latency (delay) and is bidirectional, allowing for a two-way or full duplex conversation to take place. The main shortfalls of circuit switching are provided by the inflexibility and inefficiency inherited in the network by requiring a dedicated connection each time.

As explained earlier, VoIP makes use of an IP network to transport voice in the form of data packets. IP networks were designed to carry data and do not easily carry delay-sensitive traffic such as voice and thus quality issues may arise. When an IP network becomes more congested, the quality suffers as the congestion causes packet loss or latency (the delay between one party speaking and the other party hearing). An acceptable voice conversation requires fast and sequential processing of voice packets.

As we all know IP is dependant on bandwidth availability and yes some countries have far more bandwidth readily available which is priced correctly and thus makes it viable for VoIP providers to offer a service on par with circuit-switched telephone calls.

In their acceptance of VoIP, users are going to look for the same kind of performance from IP-based voice as they get from their traditional phone services.

Do you agree? Why?

Of course they are. It’s only human to expect nothing less than you are accustomed to, isn’t it?

Technology enhancements should be just that…enhancements and thus the user cannot reasonably be expected to compromise on quality. The answer to this is education, and it will be up to the VoIP providers to educate the users in terms of types of internet connections and how these are equipped to carry VoIP traffic and the quality issues that may arise with these.

Gartner, in fact, refers to this as "five 9s reliability," meaning that the telephone network is available 99.999 percent of the time. “This translates to just over five minutes of downtime throughout an entire year. Because users have extremely high expectations for the performance of their telephone networks, there is a great deal of concern in relying on the data network to carry voice communications.”

This sounds like quite a challenge; can the current VoIP industry/technology already provide five 9s reliability?

Absolutely! But this is provider dependant, is their network capable of handling VoIP traffic? And do they sacrifice QoS for the sake of offering cheap calls? Many VoIP providers are aggressively and exclusively promoting cheap VoIP rates and conveniently brushing aside other critical factors related to voice services. This is largely due to the fact that their infrastructures are inadequate for the delivery of quality voice services.

A reliable IP-infrastructure must ensure the smooth delivery of voice and signalling packets to the VoIP device. It is here that issues such as proper traffic shaping and network design become critical. Without it, users could be facing severe service degradations like latency, jitter and crackling.

As a provider of VoIP services and our own state-of-the-art IP and MPLS network, we are able to guarantee both reduced call rates as well as a premium quality service, on a continued basis. With VoIP you get great call quality with minimum bandwidth usage. Compression technologies have evolved to allow for significant bandwidth reduction while maintaining a premium call quality, free from jitter, crackling and latency issues. It is possible to use less bandwidth but call quality will then start to degrade and this is where the VoIP providers will differ!

Quality of Service (QoS)

On a more practical level, and in line with this thinking, the key challenge in implementing VoIP and IP telephony in any company is that of quality of service (QoS). According to Gartner, “QoS involves measuring available network bandwidth, giving a higher priority to packets associated with live voice calls or other real-time or mission-critical applications, and delivering voice connections on the converged network with clarity comparable to those carried on dedicated voice networks.”

Form your perspective, do you agree, and if so, what exactly does this mean?

Gartner have it spot on! Quality of Service (QoS) is simply the ability to differentiate between IP packets (voice or data) and then route those packets based on the priority assigned to them. Since data is not time sensitive in that delays wont have as big an impact as delays on voice packets which require real time delivery, QoS for VoIP means that voice packets on a converged IP network need to be given priority over data packets like email.

In ensuring that the company infrastructure can support QOS, telecom and IT managers must select providers that understand the specific needs of voice applications, says Gartner. “Voice behaves differently from data applications and requires specialised knowledge,” the research company argues, and it therefore recommends enterprises looking to implement VoIP need to work with vendors that can demonstrate a strong understanding and established record of successful QOS delivery of both voice and data.

Can you outline the strengths/understanding/track record Denwa has in delivering QOS?

In anticipation of market demands for reliable VoIP services, we’ve made sure that we have all the bandwidth, systems and expertise in place to handle the increase in traffic volume. VoIP is in our DNA at Denwa and we'll continue to deliver it time and time again with the best quality and technical expertise to troubleshoot any issues our customers experience.

The research organisation also believes that because network convergence introduces a host of new challenges for network managers, real-time monitoring for QoS is a burden that many are not prepared to assume. “As a result, some IT organisations prefer to delegate this monitoring to a service provider, either as a short-term solution while the in-house team becomes competent at performing the task internally, or as a long-term service approach. This is often extremely valuable to highly distributed organisations facing the task of monitoring numerous sites but still requiring centralised management capabilities.”

If you're not sure about VoIP technology or would like to explore our VoIP services for business, contact Denwa and we'll step you through our products and services.

Or alternatively read about our SIP trunk service.