Good and bad VoIP: What to look for

The term Voice over IP, or VoIP has been thrown around by telecoms salesmen for many years. However, there appears to be a growing confusion about what it is and what can be achieved,along with why someone would want or not want VoIP telephony services.

What is VoIP?

VoIP is a term that refers to any telephone signal that is translated into data packets, sent across a network, and then translated back into audio. Imagine you and your colleague are on your computers. You use your microphone to record a sound into your computer and then attach the file and e-mail it to you colleague. They open the attachment, listen to it, and then compose their own response and emails it back to you. Now repeat this much faster and this, essentially, is what VoIP is.

To get to the essence of what VoIP is we must first unde​rstand what IP is. IP is a protocol developed by Xerox PARC and US government DARPA back in the 1970s. The protocol eventually became the driving force behind the Internet and became extremely popular, primarily due to the fact that anyone could access it on a multitude of devices.

You simply needed a connection to the "backbone" of the Internet to enable you to get to any other computer in the world that was also connected to the backbone. Now there may be 30 or 40 routers and about a dozen computers between you and the computer you want to talk to and you have to go through each of them (known as a "hop") to get to your destination. Each of these hops introduces latency, a phenomenon which slows down the traffic. Generally speaking, the more hops you go through, the slower your connection is. This can also be affected by slow or poor quality routers, outages (requiring you to take another path) or congestion.

To see this action, open a windows command prompt on your computer, and type "tracert" into the prompt and hit "Enter". You will now see each hop listed and the time in milliseconds (ms.) it takes to get to that point. Now imagine your voice traveling over this same path. Every time the packet stops, a delay to the sound is being received. This can present various problems in a telephone call including a broken speech, delays and the appearance of echo.

2 Breeds of VoIP – Good and Bad

There are 2 distinct type of VoIP traffic. A number of solutions use the public Internet to carry the traffic, while others use a private secured network. Both operate generally at the same, yet using the public internet can bring significantly more problems than a private secure network.

For example, you have a branch office in Manchester and you are at your corporate office located in Preston. There is a private communications link between the 2 sites and you now want to make a call from your desk in Preston to your colleague in Manchester. If your IT team has done their job correctly, you should have a good quality link. In addition, there should only be 3 hops. Firstly from your phone to the start of the link, then going across the link and finally internally to your colleague in Manchester.

An alternative to the dedicated communications link is for you both to be connected to the same internet provider. Even though you are using the public internet, the traffic is only travelling over the ISP's own lines and their network, resulting in minimal delay being introduced, and most likely, a good quality call experience.

Now suppose you want to ring a customer in Berlin. While there is only a small number of hops between your offices, to get to Berlin you may need 18 hops and the quality of the call will deteriorate.

So as you can see, a large bandwidth internet link is not the biggest issue. Latency can affect the call quality and the user experience.

Bad VoIP Sources

Any traffic that travels over the public internet is going to hit problems. Even if you are on a high speed broadband connection at home, when you're downloading something on Sky OnDemand, watching BBC iPlayer or even doing your security updates on your PC, your connection will slow down and the quality of a VoIP phone call will drop.

If you are connecting between businesses and the Internet connection that you are using is congested by your staff sending emails and web browsing, then you will also experience problems.

Also, the introduction of "free" calling services, such as Skype and Viber are potential causes of trouble. These products utilise the Internet and the connection quality that you will have with them is subject to the same problems as any "public" connection.

These products may have a place in a consumer environment, such as a residence where the quality is of lower importance, however how will your business appear to a potential customer when you cut out frequently or drop a call with them.

Good VoIP Sources

So Good VoIP comes from a good network design, and reducing or eliminating traffic going across the "public" Internet. The example with the branch offices being connected to the same ISP can be considered Good, as the provider has control to design it correctly.

Another source is a high quality hosted phone system on a reputable telecoms provider's network, such as Vodafone One Net. These solutions are usually connected directly to the providers network and don't use the public internet.

If the idea of removing your PBX frightens you, then the carrier could, on selected systems, put a dedicated VoIP link from your phone system to the carriers networks. These are called SIP trunks. Many operators are utilizing VoIP within their own private networks. They have discovered that it is considerably cheaper to build a data network and simply pass the voice traffic across it. Since these networks are internal to the carrier and well maintained by its network staff, the connections are generally very reliable and sound as good as a standard fibre-optic phone call.