An Introduction to VoIP

(Voice Over Internet Protocol)

For the past several years, a number of NOTO members have attempted to find a technology to replace their expensive and unreliable radio phones. Most have looked at Voice over Internet Protocol or VoIP, delivered over a satellite internet connection. Tom Metzner has taken the time to document his experiences over the past several years, both good and bad, and has kept the industry up-to-date on his struggles with VoIP over satellite in his postings on the NOTO message board.

Tom’s article in this issue documents his experience and provides some clear do’s and dont’s for anybody looking for this sort of communications solution. What follows is an attempt to provide an overview of the basics of voice services using satellite internet, and hopefully it can serve as an introduction to Tom’s article for those who may feel a bit overwhelmed by some of the technical terms.

What is VOIP

Voice over Internet Protocol systems have grown tremendously in popularity over the past several years, since they offer the promise of cheap, virtually unlimited long distance phone service. VoIP services are available from a number of providers, such as Vonage, and there are also software based VoIP solutions, like SKYPE that simply run off your computer.

All of these systems depend on the use of a high speed internet connection such as cable internet or DSL. In the case of packaged solutions such as Vonage, you purchase their VoIP phone, sign up for service, and connect the phone to your high speed internet connection. The connection is simply shared with your existing computer connection, and the VoIP phone functions very much like a regular phone, allowing you to make and receive calls.

An added advantage of a VoIP phone is that you can take your phone and phone number with you. When you go to a sports show, you simply plug your VoIP device into the high speed internet connection at your hotel, and your number works exactly the same as it would at home or at the lodge.

Using VOIP with Satellite

The problem at the lodge, of course, has been gaining access to high speed internet service. Over the past few years, a number of tourist operators have installed the Hughes Directway high speed satellite internet system, and most have obtained pretty satisfactory results for internet use.

However, most attempts to use VoIP devices, like the Vonage phone with this satellite system have produced completely unsatisfactory results. Two main factors account for this difficulty, consistent speed and latency.

Latency refers to the time it takes for the signal to get to a satellite located approximately 30,000 miles away and back. This time delay causes a variety of problems, primarily delays on connection that lead to an odd silence when you begin a call. The more serious problem, however, has been the issue of maintaining enough connection speed, and maintaining that minimum speed consistently. If the speed goes up and down a bit during normal internet use, it isn’t even noticed. However, if it drops during VoIP, the sound becomes choppy and broken up.

Two way satellite internet connections advertise two speeds, download and upload. These systems allow you to receive data from the satellite much faster than you can send it to the satellite. This is a very way to optimize channel capacity for most applications, since browsing a web page, for example, requires you to receive very large amounts of data, while sending very little.

However, voice service requires that you maintain sufficient speed both ways, and, as you’ll see in Tom’s article, he found that the Hughes system was not able to sustain sufficient speed to make the service work reliably.

Is it the connection or is it the phone?

You’ll also see in Tom’s article that one of the challenges he faced was figuring out whether the problem was with his satellite internet connection or with his VoIP system. The advertised speed for his satellite connection appeared to be sufficient to handle voice. However, satellite internet systems use data compression to improve performance. Unfortunately, compression works better on some kinds of data than others, so the actual speed for the voice data being sent may have been much lower than the published figures.

Which VoIP solution you use can also make a difference. Because VoIP systems turn voice into digital data, they perform their own data compression. The programs that do this, called CODECs (coder/decoders) vary from one system to another. Most systems, in fact, use multiple CODECs, and switch between them on the fly, depending on connection speed.

So, under the circumstances, switching from one VoIP system to another might make sense, since a particular set of CODECs may be more suitable for satellite.

The Ka Band Solution

Over the past year or so, a new high speed satellite internet service has appeared. Telesat Canada launched a new satellite that featured service in the higher frequency Ka band. Theoretically, Ka band provides the advantage of smaller dishes. In practice, this means that a similar size dish produces a stronger signal.

A very significant difference with Telesat’s Ka band service, however, is their use of “spot beams”. This simply means that the satellite signal is concentrated in a limited area, rather than reaching all of North America, for example.

Spot beams create two major advantages. First of all, the signal is stronger. In addition, use of spot beams means that a channel can be used in more than one area, increasing capacity and reducing cost.

What this all means is that the current Ka band service is faster and cheaper than the previous Hughes Ku band system. It is this new Ka band service that finally gave Tom the working VoIP solution that he discusses in his article.

Where to from here?

Now is probably a good to time to inject notes of both caution and optimism. Although Tom’s system seems to be working very well right now, will it continue to work as the Telesat satellite gains more customers, or will the increased load drag the speed down below reliable levels?

On the other hand, the geeks working for the various VoIP providers are always working to write new CODECs, so the connection speed requirements keep coming down.

Our current VoIP solutions, even the cheap or free ones, work very well indeed under many circumstances. I have the SKYPE software installed on my computer here in the NOTO office, and the folks I phone from the computer probably don’t even know I’m not using a “real phone”. It works exceptionally well “computer to computer”, and if you’re ever curious about it, I suggest you download the free software and give it a try. Feel free to give me a call when you do – you can search for me on SKYPE as Doug Reynolds in North Bay.

As Tom points out in his article, reliable communications are essential for our industry, and becoming more important all the time. It looks like we are finally making some progress on this problem, thanks in no small measure to folks like Tom who have kept experimenting and taken the time to share their results with the rest of us. 

This article was taken from pages 14 & 15 of NOTO's "The Outfitter" publication, Fall 2006 Issue


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