One consideration that needs to be made in choosing VoIP is the fact that it uses considerable bandwidth. VoIP requires a high-speed Internet connection for reliable operation, and most high-speed connections have a limited amount of bandwidth available. This article will discuss some of the aspects of VoIP bandwidth.

Most residential users of VoIP will not experience any bandwidth problems with their existing high-speed Internet connection. These connections typically provide more bandwidth than is necessary for quality VoIP calls to be made. However, it would still be a good idea to find out how much bandwidth you have available and how much is required by your VoIP service. For business users with multiple lines, bandwidth is a serious consideration for VoIP, so more care needs to be taken.

The minimum bandwidth of a high-speed Internet connection is approximately 384kbps (or kilobits per second). The maximum can be as much as 7mbps (megabits per second) or more. A VoIP call made with the highest quality setting will require around 100kbps of this bandwidth. A fax sent over VoIP will require about the same amount. So, as you can see, most connections should easily provide enough bandwidth for one or two simultaneous voice calls. But it would be a good idea for you to check how much bandwidth you have available.

Many VoIP providers have utilities posted on their site that allow you to check for available bandwidth. They usually do this by downloading one or several large files to your hard drive. This is a good way to check bandwidth, as file downloads will use as much as is available. They then calculate the available bandwidth based on the size of the file and the time that it took to download. You should run several of these tests at one time and average the results. You should also run these tests at several different times during the day. Keep in mind that response in general is slowest during business hours, as this is when the Internet is experiencing the heaviest load.

Also, keep in mind that you need enough bandwidth to cover normal Internet usage as well as VoIP calls. This will likely not be a problem with normal surfing, but activities such as large file or image downloads consume a large amount of bandwidth. So you may want to try these tests while someone is using the Internet from another PC. Have them download some files or images while you are running your tests - the test results will show if the bandwidth goes below the minimum required for a quality VoIP call.

Another thing to keep in mind is that while voice calls are somewhat tolerant of reduced bandwidth, sending and receiving of faxes is not. Fax protocols do not allow for missing or heavily delayed packets, so a fax transmission may not complete if sufficient bandwidth is not available. You should make sure that you have enough bandwidth available to handle each voice or fax line at 100kbps each, plus enough to handle your normal Internet activity.

If you have concerns about available bandwidth, you should contact your Internet service provider. Most have more than one bandwidth setting, and yours may be at the minimum. But keep in mind that you will likely pay a higher monthly fee for a higher bandwidth setting. Also, if you have DSL access, the available bandwidth is dependent on the quality of the telephone wiring between your home or business and the nearest wiring station. It may be that your bandwidth limit was determined by this check before your service was installed.

So how will I know if I am having bandwidth problems? If you are already using VoIP, bandwidth problems will most likely show up in the form of calls “breaking up” or (rarely) being “dropped” - similar to what you sometimes experience with cellular calls. If you have either of these symptoms, then limited bandwidth could likely be the cause.

Bandwidth is a consideration when using VoIP, but as you can see, it should not be a problem for most users. Running a few simple tests can provide you with some assurance that your VoIP experience will be a pleasant one.

This article "VoIP Bandwidth Requirements" is Copyright 2006 Compare-VoIP.net and may not be reproduced.

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